An α-ketoglutarate conformational switch controls iron accessibility, activation, and substrate selection of the human FTO protein.

The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N6-methyladenosine (m6A), N1-methyladenosine (m1A), 3-methylthymine (m3T), and 3-methyluracil (m3U) in single-stranded nucleic acids. It is well established that the catalytic activity of FTO proceeds via two coupled reactions. The first reaction involves decarboxylation of alpha-ketoglutarate (αKG) and formation of an oxyferryl species. In the second reaction, the oxyferryl intermediate oxidizes the methylated nucleic acid to reestablish Fe(II) and the canonical base. However, it remains unclear how binding of the nucleic acid activates the αKG decarboxylation reaction and why FTO demethylates different methyl modifications at different rates. Here, we investigate the interaction of FTO with 5-mer DNA oligos incorporating the m6A, m1A, or m3T modifications using solution NMR, molecular dynamics (MD) simulations, and enzymatic assays. We show that binding of the nucleic acid to FTO activates a two-state conformational equilibrium in the αKG cosubstrate that modulates the O2 accessibility of the Fe(II) catalyst. Notably, the substrates that provide better stabilization to the αKG conformation in which Fe(II) is exposed to O2 are demethylated more efficiently by FTO. These results indicate that i) binding of the methylated nucleic acid is required to expose the catalytic metal to O2 and activate the αKG decarboxylation reaction, and ii) the measured turnover of the demethylation reaction (which is an ensemble average over the entire sample) depends on the ability of the methylated base to favor the Fe(II) state accessible to O2.

Branched stented anastomosis frozen elephant trunk repair: Early results from a physician-sponsored investigational device exemption study.

BACKGROUND: Multisegment thoracic aortic disease typically requires total aortic arch replacement, affects a heterogenous population, and carries a high risk even at centers of excellence. Risk has been associated with the duration of operation and complexity of repair. A novel branched stented anastomosis frozen elephant trunk repair (B-SAFER) technique has been developed at our center and is currently being studied as a physician-sponsored investigation device exemption (PS-IDE). OBJECTIVE: This study aimed to assess the early safety of using this investigational technique to treat the proximal aorta in subjects with aortic disease involving multiple segments. METHODS: This prospective, single center, nonrandomized study enrolled patients undergoing B-SAFER for acute aortic syndrome (n = 73), aortic aneurysm with chronic aortic dissection (n = 68), degenerative aortic aneurysm (n = 33), or congenital aortic arch disease (n = 4). Devices are delivered antegrade under hypothermic circulatory arrest, and the arch reconstruction is performed as a single anastomosis single stent (SASS; n = 70), single anastomosis multiple stent (SAMA; n = 68), multiple anastomosis single stent (MASS; n = 21), or multiple anastomosis multiple stent (MAMS; n = 16) reconstruction. The primary safety endpoints were operative mortality, disabling stroke, and paraparesis/paralysis. RESULTS: Between May 27, 2021, and December 31, 2022, 178 patients underwent B-SAFER in the configurations and for the indications as described above. The median patient age was 65 years (range, 21 to 85 years), and 52 (29%) were female. The median cardiopulmonary bypass time was 188 minutes (interquartile range [IQR], 155 to 226 minutes), and 97% of the patients underwent repair with antegrade brain perfusion for a median of 46 minutes (IQR, 38 to 61 minutes). Operative mortality occurred in 10 patients (5.6%, including 6 [8.2%] with acute dissection, 2 [2.9%] with chronic dissection, 2 [6.1%] with degenerative aneurysm, and 0 with a congenital disorder), disabling stroke in 5 patients (2.9%), and paraparesis in 1 patient. Other serious complications included respiratory failure (n = 20; 11.4%) and acute kidney injury (n = 18; 10%). Thirty-two patients (18%) had undergone second-stage repairs (28 endovascular and 4 open), with 1 operative mortality after that procedure due to distal rupture. Estimated survival was 95% at 30 days, 88% at 90 days, 84% at 6 months, and 79% at 1 year. One-year survival differed by indication (72% for acute dissection, 91% for chronic dissection, 71% for degenerative aneurysm, and 100% for congenital disorders). CONCLUSIONS: The B-SAFER technique for total arch replacement in a complex cohort of patients with various indications for surgery is a safe and reproducible operation, as demonstrated by the early results from a very inclusive PS-IDE study. Further follow-up and analysis will help refine the technique. Novel devices to perform this procedure should be developed.

Towards a better understanding of human iNKT cell subpopulations for improved clinical outcomes.

Invariant natural killer T (iNKT) cells are a unique T lymphocyte population expressing semi-invariant T cell receptors (TCRs) that recognise lipid antigens presented by CD1d. iNKT cells exhibit potent anti-tumour activity through direct killing mechanisms and indirectly through triggering the activation of other anti-tumour immune cells. Because of their ability to induce potent anti-tumour responses, particularly when activated by the strong iNKT agonist αGalCer, they have been the subject of intense research to harness iNKT cell-targeted immunotherapies for cancer treatment. However, despite potent anti-tumour efficacy in pre-clinical models, the translation of iNKT cell immunotherapy into human cancer patients has been less successful. This review provides an overview of iNKT cell biology and why they are of interest within the context of cancer immunology. We focus on the iNKT anti-tumour response, the seminal studies that first reported iNKT cytotoxicity, their anti-tumour mechanisms, and the various described subsets within the iNKT cell repertoire. Finally, we discuss several barriers to the successful utilisation of iNKT cells in human cancer immunotherapy, what is required for a better understanding of human iNKT cells, and the future perspectives facilitating their exploitation for improved clinical outcomes.

Serratus anterior and pectoralis plane blocks for robotically assisted mitral valve repair: a randomised clinical trial.

BACKGROUND: Minimally invasive cardiac surgery provokes substantial pain and therefore analgesic consumption. The effect of fascial plane blocks on analgesic efficacy and overall patient satisfaction remains unclear. We therefore tested the primary hypothesis that fascial plane blocks improve overall benefit analgesia score (OBAS) during the initial 3 days after robotically assisted mitral valve repair. Secondarily, we tested the hypotheses that blocks reduce opioid consumption and improve respiratory mechanics. METHODS: Adults scheduled for robotically assisted mitral valve repairs were randomised to combined pectoralis II and serratus anterior plane blocks or to routine analgesia. The blocks were ultrasound-guided and used a mixture of plain and liposomal bupivacaine. OBAS was measured daily on postoperative Days 1-3 and were analysed with linear mixed effects modelling. Opioid consumption was assessed with a simple linear regression model and respiratory mechanics with a linear mixed model. RESULTS: As planned, we enrolled 194 patients, with 98 assigned to blocks and 96 to routine analgesic management. There was neither time-by-treatment interaction (P=0.67) nor treatment effect on total OBAS over postoperative Days 1-3 with a median difference of 0.08 (95% confidence interval [CI]: -0.50 to 0.67; P=0.69) and an estimated ratio of geometric means of 0.98 (95% CI: 0.85-1.13; P=0.75). There was no evidence of a treatment effect on cumulative opioid consumption or respiratory mechanics. Average pain scores on each postoperative day were similarly low in both groups. CONCLUSIONS: Serratus anterior and pectoralis plane blocks did not improve postoperative analgesia, cumulative opioid consumption, or respiratory mechanics during the initial 3 days after robotically assisted mitral valve repair. CLINICAL TRIAL REGISTRATION: NCT03743194.

Early mortality and neurologic outcomes following mitral valve surgery in the very elderly.

OBJECTIVES: Valve repair is the gold standard for treatment of degenerative mitral valve disease. As the population ages, patients undergoing valve degeneration and therefore considered for mitral valve surgery will naturally be getting older. We sought to evaluate whether mitral repair retained a survival advantage over replacement in patients ≥80 years old. METHODS: A retrospective cohort study was performed using data acquired from the United Kingdom National Adult Cardiac Surgery Audit for the outcomes of in-hospital mortality and postoperative cerebrovascular event (CVA). Individual multivariable logistic regression models were created to investigate adjusted associations between these outcomes and type of mitral valve operation, repair or replacement. Additionally, associations between the individual model parameters and in-hospital mortality and CVA were investigated. RESULTS: A total of 1140 patients underwent mitral repair (66.4%, median age 82.3), and 577 patients underwent mitral replacement (33.6%, median age 82.1). The overall age range was 80-92. The incidence of in-hospital mortality favored the repair group (4.4% vs. 8.3%, p = .001). Multivariable logistic regression modeling demonstrated an increased adjusted odds of in-hospital mortality for mitral valve replacement (MVR) (odd ratio [OR]: 2.01, 1.15-3.50, p = .01). The only other parameter associated with an increased adjusted odds of in-hospital mortality was postoperative dialysis (OR: 14.2, 7.67-26.5, p < .001). There was not a demonstrated association between MVR and perioperative CVA (OR: 1.11, 0.49-2.4, p = .8). CONCLUSIONS: In patients ≥80 years old, mitral valve repair (MVr) was shown to be associated with a decreased adjusted odds of mortality, with a null association with CVA. These results suggest that, if feasible, MVr should remain the preferred management strategy, even in the very elderly.

Reoperation after early and late failure of mitral valve repair for degenerative disease.

OBJECTIVES: To determine mechanisms of early and late failure after mitral valve repair for degenerative disease, identify factors associated with re-repair, and evaluate durability of re-repair. METHODS: From January 2008 to July 2020, 330 reoperations were performed for recurrent mitral valve dysfunction after initial valve repair for degenerative disease. Mechanisms of repair failure were determined by review of preoperative imaging and operative reports. Multivariable analysis was performed to identify factors associated with likelihood of re-repair or replacement. Durability of re-repair was assessed using longitudinal analysis of postoperative echo data. RESULTS: Eighty-five of 330 (26%) reoperations were performed for early repair failure within 1 year and 245/330 (74%) for late failure thereafter. Suture/annuloplasty dehiscence, systolic anterior motion, hemolysis, and ventricular remodeling were more common mechanisms of early failure and disease progression and fibrosis late failure. Forty percent (34/85) of early failures were re-repaired versus 24% (59/245) of late failures. Re-repair was more common than replacement in recent years and was associated with earlier reoperation (median 1.5 vs 3.9 years; P = .0001). No in-hospital deaths occurred after re-repair; 2 patients (0.8%) died after valve replacement. Freedom from severe mitral regurgitation after re-repair was 93% at 7 years. CONCLUSIONS: Mitral valve re-repair can be performed with low rates of mortality and morbidity for early and late valve dysfunction. Mechanisms of early repair failure differ from those of late failure and are generally more amenable to re-repair. In selected patients who present after failed repair, we prefer mitral re-repair to valve replacement whenever technically feasible.

Two-year outcomes after transcatheter aortic valve-in-valve implantation in degenerated surgical valves.

BACKGROUND: Transcatheter aortic valve-in-valve implantation (ViV-TAVI) has emerged in recent years as a safe alternative to redo surgery in high-risk patients. Although early results are encouraging, data beyond short-term outcomes are lacking. Herein, we aimed to assess the 2-year outcomes after ViV-TAVI. METHODS: Patients undergoing ViV-TAVI for degenerated surgical valves between 2013 and 2019 at the Cleveland Clinic were reviewed. The coprimary endpoints were all-cause mortality and congestive heart failure (CHF) hospitalizations. We used time-to-event analyses to assess the primary outcomes. Further, we measured the changes in transvalvular gradients and the incidence of structural valve deterioration (SVD). RESULTS: One hundred and eighty-eight patients were studied (mean age = 76 years; 65% males). At 2 years of follow-up, all-cause mortality and CHF hospitalizations occurred in 15 (8%) and 28 (14.9%) patients, respectively. On multivariable analysis, the postprocedural length of stay was a significant predictor for both all-cause mortality (hazard ratio [HR] = 1.1; 95% confidence interval [CI]: 1.01, 1.19) and CHF hospitalization (HR = 1.16; 95% CI: 1.07, 1.27). However, the internal diameter of the surgical valve was not associated with significant differences in both primary endpoints. For hemodynamic outcomes, nine patients (4.8%) developed SVD. The mean and peak transvalvular pressure gradients remained stable over the follow-up period. CONCLUSION: ViV-TAVI for degenerated surgical valves was associated with favorable 2-year clinical and hemodynamic outcomes. Further studies are needed to better understand the role of ViV-TAVI as a treatment option in the life management of aortic valve disease.

Rare Germline Variants Are Associated with Rapid Biochemical Recurrence After Radical Prostate Cancer Treatment: A Pan Prostate Cancer Group Study.

BACKGROUND: Germline variants explain more than a third of prostate cancer (PrCa) risk, but very few associations have been identified between heritable factors and clinical progression. OBJECTIVE: To find rare germline variants that predict time to biochemical recurrence (BCR) after radical treatment in men with PrCa and understand the genetic factors associated with such progression. DESIGN, SETTING, AND PARTICIPANTS: Whole-genome sequencing data from blood DNA were analysed for 850 PrCa patients with radical treatment from the Pan Prostate Cancer Group (PPCG) consortium from the UK, Canada, Germany, Australia, and France. Findings were validated using 383 patients from The Cancer Genome Atlas (TCGA) dataset. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: A total of 15,822 rare (MAF <1%) predicted-deleterious coding germline mutations were identified. Optimal multifactor and univariate Cox regression models were built to predict time to BCR after radical treatment, using germline variants grouped by functionally annotated gene sets. Models were tested for robustness using bootstrap resampling. RESULTS AND LIMITATIONS: Optimal Cox regression multifactor models showed that rare predicted-deleterious germline variants in "Hallmark" gene sets were consistently associated with altered time to BCR. Three gene sets had a statistically significant association with risk-elevated outcome when modelling all samples: PI3K/AKT/mTOR, Inflammatory response, and KRAS signalling (up). PI3K/AKT/mTOR and KRAS signalling (up) were also associated among patients with higher-grade cancer, as were Pancreas-beta cells, TNFA signalling via NKFB, and Hypoxia, the latter of which was validated in the independent TCGA dataset. CONCLUSIONS: We demonstrate for the first time that rare deleterious coding germline variants robustly associate with time to BCR after radical treatment, including cohort-independent validation. Our findings suggest that germline testing at diagnosis could aid clinical decisions by stratifying patients for differential clinical management. PATIENT SUMMARY: Prostate cancer patients with particular genetic mutations have a higher chance of relapsing after initial radical treatment, potentially providing opportunities to identify patients who might need additional treatments earlier.

A conservative screening algorithm to determine candidacy for robotic mitral valve surgery.

OBJECTIVE: Patient selection for robotically assisted mitral valve repair remains controversial. We assessed outcomes of a conservative screening algorithm developed to select patients with degenerative mitral valve disease for robotic surgery. METHODS: From January 2014 to January 2019, a screening algorithm that included transthoracic echocardiography and computed tomography scanning was rigorously applied by 3 surgeons to assess candidacy of 1000 consecutive patients with isolated degenerative mitral valve disease (age 58 ± 11 years, 67% male) for robotic surgery. Screening results and hospital outcomes of those selected for robotic versus sternotomy approaches were compared. RESULTS: With application of the screening algorithm, 605 patients were selected for robotic surgery. Common reasons for sternotomy (n = 395) were aortoiliac atherosclerosis (n = 74/292, 25%), femoral artery diameter <7 mm (n = 60/292, 20%), mitral annular calcification (n = 83/390, 21%), aortic regurgitation (n = 100/391, 26%), and reduced left ventricular function (n = 126/391, 32%). Mitral valve repair was accomplished in 996. Compared with sternotomy, patients undergoing robotic surgery had less new-onset atrial fibrillation (n = 144/582, 25% vs n = 125/373, 34%; P = .002), fewer red blood cell transfusions (n = 61/601, 10% vs 69/395, 17%; P < .001), and shorter hospital stay (5.2 ± 2.9 days vs 5.9 ± 2.1 days; P < .001). No hospital deaths occurred, and occurrence of postoperative stroke in the robotic (n = 3/605, 0.50%) and sternotomy (n = 4/395, 1.0%; P = .3) groups was similar. CONCLUSIONS: This conservative screening algorithm qualified 60% of patients with isolated degenerative mitral valve disease for robotic surgery. Outcomes were comparable with those obtained with sternotomy, validating this as an approach to select patients for robotic mitral valve surgery.

Techniques for Mitral Valve Re-repair.

The emergence of mitral valve repair as the preferred treatment for severe mitral regurgitation (MR) caused by degenerative disease has been accompanied by an increasing number of valve repair failures seen by surgeons. Consequently, the feasibility of valve re-repair vs valve replacement at the time of reoperation has become a valid clinical consideration. In this report we explore the mechanisms of mitral valve repair failure as well as factors that meaningfully influence the likelihood of a successful re-repair. We provide illustrations of techniques for re-repair that we have used with reliable success, informed by the mechanism of repair failure. Lastly, we share our outcomes for mitral valve re-repair over the last 5 years and discuss our experience using the techniques illustrated in this report.

Endoscopic vein harvesting.

Coronary artery bypass grafting is the most common cardiac surgical procedure performed worldwide and the long saphenous vein the most common conduit for this. When performed as an open vein harvest (OVH), the incision on each leg can be up to 85cm long, making it the longest incision of any routine procedure. This confers a high degree of morbidity to the procedure. Endoscopic vein harvest (EVH) methods were popularised over two decades ago, demonstrating significant benefits over OVH in terms of leg wound complications including surgical site infections. They also appeared to hasten return to usual activities and wound healing and became popular particularly in North America. Subgroup analyses of two trials designed for other purposes created a period of uncertainty between 2009-2013 while the impact of endoscopic vein harvesting on vein graft patency and major adverse cardiac events was scrutinised. Large observational studies debunked the findings of increased mortality in the short-term, allowing practitioners and governing bodies to regain some confidence in the procedure. A well designed, adequately powered, randomised controlled trial published in 2019 also definitively demonstrated that there was no increase in death, myocardial infarction or repeat revascularisation with endoscopic vein harvest. Endoscopic vein harvest is a Class IIa indication in European Association of Cardio-Thoracic Surgery (EACTS) and a Class I indication in International Society of Minimally Invasive Cardiac Surgery (ISMICS) guidelines.