Orthogonal cytokine engineering enables novel synthetic effector states escaping canonical exhaustion in tumor-rejecting CD8+ T cells

To date, no immunotherapy approaches have managed to fully overcome T-cell exhaustion, which remains a mandatory fate for chronically activated effector cells and a major therapeutic challenge. Understanding how to reprogram CD8+ tumor-infiltrating lymphocytes away from exhausted effector states remains an elusive goal. Our work provides evidence that orthogonal gene engineering of T cells to secrete an interleukin (IL)-2 variant binding the IL-2Rβγ receptor and the alarmin IL-33 reprogrammed adoptively transferred T cells to acquire a novel, synthetic effector state, which deviated from canonical exhaustion and displayed superior effector functions. These cells successfully overcame homeostatic barriers in the host and led-in the absence of lymphodepletion or exogenous cytokine support-to high levels of engraftment and tumor regression. Our work unlocks a new opportunity of rationally engineering synthetic CD8+ T-cell states endowed with the ability to avoid exhaustion and control advanced solid tumors.

Effects of catheter ablation on left atrial performance in different types of atrial fibrillation: a strain study

Background

Atrial structural and functional changes may develop as a result of catheter ablation (CA) in patients with paroxysmal and persistent atrial fibrillation (AF). However, the relation between AF recurrence and atrial performance following CA is still under debate. Our aim is to describe the long-term effects of CA on LA remodeling and its correlates to the maintenance of sinus rhythm (SR).

Methods

We prospectively enrolled 178 consecutive patients (age: 63±9 years, 35% females) with paroxysmal AF undergoing first-CA (67%) or redo-CA (22%), and 20 individuals (11%) with long-standing persistent AF (PAF) undergoing first CA. All patients underwent comprehensive transthoracic echocardiography at baseline and at 12-month follow-up, including the assessment of reservoir and contractile strain (LAS) using two dimensional speckle tracking echocardiography in all three apical views. The study population was divided in two sub-groups according to AF recurrence during follow-up.

Results

During one-year follow-up, 144 (81%) patients maintained SR whereas 34 (19%) patients had AF recurrence [first-CA group 16 (13%), redo-CA group 8 (20%) and PAF group 10 (50%)]. Improvement of LAS was observed only in patients with paroxysmal and long-standing persistent AF who underwent the first CA and who remained in SR (Figure 1A, 1C). In contrast, recurrent AF was associated with absence of LAS improvement (Figure 1A, 1C). Different time course of LA performance was observed in the redo-CA group, i.e. LAS remained unchanged from baseline regardless of long-term maintenance of SR (Figure 1B). Moreover, at follow-up, no significant differences in LAS between redo-CA patients with SR versus AF were observed. Of note, in patients with long-standing persistent AF and SR, follow-up LAS increased to values observed in the redo-CA group.

Conclusion

LA performance following CA is strongly affected by complex interplay between extent of atrial electro-structural remodeling and CA procedure. Repeated wide CA might affects negatively LA compliance and contractility despite SR restoration.

Figure 1. Reservoir and contractile LAS at Baseline and 12-month follow-up in the First-CA (1A), the Redo-CA (1B) and the long-standing persistent AF (1C) groups in patients who maintained SR versus patients who had AF recurrence. *p value <0.05 (baseline vs. follow-up).

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): International PhD programme in Cardiovascular Pathophysiology and Therapeutics (CardioPaTh).

The NAD-Booster Nicotinamide Riboside Potently Stimulates Hematopoiesis through Increased Mitochondrial Clearance

It has been recently shown that increased oxidative phosphorylation, as reflected by increased mitochondrial activity, together with impairment of the mitochondrial stress response, can severely compromise hematopoietic stem cell (HSC) regeneration. Here we show that the NAD⁺-boosting agent nicotinamide riboside (NR) reduces mitochondrial activity within HSCs through increased mitochondrial clearance, leading to increased asymmetric HSC divisions. NR dietary supplementation results in a significantly enlarged pool of progenitors, without concurrent HSC exhaustion, improves survival by 80%, and accelerates blood recovery after murine lethal irradiation and limiting-HSC transplantation. In immune-deficient mice, NR increased the production of human leucocytes from hCD34+ progenitors. Our work demonstrates for the first time a positive effect of NAD⁺-boosting strategies on the most primitive blood stem cells, establishing a link between HSC mitochondrial stress, mitophagy, and stem-cell fate decision, and unveiling the potential of NR to improve recovery of patients suffering from hematological failure including post chemo- and radiotherapy.

1039 Time course of left atrial performance in patients with paroxysmal atrial fibrillation undergoing radio-frequency catheter isolation of pulmonary veins

Background

Radio-frequency catheter isolation of pulmonary veins (RF-PVI) is associated with changes of left atrial (LA) structure and function. However, there is limited knowledge regarding the long-term impact of successful RF-PVI on the LA mechanics. The aim of the current study was to assess the time course of LA performance in patients with paroxysmal atrial fibrillation (pAF) undergoing RF-PVI.

Methods

The study population included 24 consecutive patients (age:62 ± 21 years; 66% male) with symptomatic pAF and preserved left ventricular ejection fraction (≥50%) undergoing the first RF-PVI and 23 healthy controls. A comprehensive echocardiographic examination was performed one day before and 1 day, 3- and 12- months after RF-PVI. The reservoir, conduit and contractile LA strain (LAS), strain rate (LASR) and mechanical dispersion (LAMD) were assessed using two-dimensional speckle tracking echocardiography in apical views.

Results

At baseline, patients with pAF showed a significant reduction of all three components of LAS and LASR compared with controls (all p < 0.01). At 1 day after RF-PVI, LAS and LASR showed significant decrease compared with baseline (all p < 0.05) (figure). At 3-month follow up, LAS and LASR recovered to baseline values while LAMD showed a significant improvement (77ms vs 58ms, p = 0.003). At 12-month follow up, both reservoir and contractile LAS showed further improvement compared to 3-month values (31% vs 27%, and 15% vs 13%, both p < 0.05). Yet, even after 12 months, LAS values remained significantly lower compared with healthy controls (p < 0.05). LA emptying fraction was restored and LA end-systolic (max) and end-diastolic (min) volume index showed a significant decrease compared to baseline and 3-month values (all p < 0.05).

Conclusion

Successful RF-PVI is associated with acute decrease in LAS, followed by recovery to baseline values within 3 months and further improvement during one year. Reservoir and contractile LAS appears to be the most clinically useful indices to monitor LA performance in patients with pAF undergoing RF-PVI.

Figure

Time course of LA reservoir and contractile strain, LA max and min volume index, and LA mechanical dispersion (Baseline, 1-day FUP, 3- and 12-month FUP).

Abstract 1039 Figure.

554 Atrial mechanical dispersion in patients with atrial fibrillation undergoing catheter ablation: a strain study

Background

Atrial mechanical dispersion (MD) might increase the risk of atrial fibrillation (AF). However, the data on atrial mechanical dispersion in patients with AF undergoing catheter ablation (CA) are scarce.

Purpose

To describe effects of CA on inter- and left intra-atrial MD in patients with different sub-types of AF undergoing CA.

Methods

We prospectively enrolled 138 symptomatic patients (age: 63 ± 21 years, 32% females) with paroxysmal AF undergoing first (81%) or redo (19%) CA during sinus rhythm, and 20 individuals (age: 66 ± 23 years, 20% females) with long-standing persistent AF undergoing first CA during AF. All patients had normal (≥50%) left ventricular ejection fraction. Control group consisted of 23 healthy controls. The atrial strain and strain rate (SR) were assessed using the two-dimensional speckle tracking echocardiography as average of segmental values in all apical views for LA and in four chamber (4CH) apical view for RA. We quantified inter-atrial MD as the standard deviation of time from the onset of the P wave to peak negative strain curves (Figure 1), and left intra-atrial MD as the standard deviation of time from the onset of QRS wave to peak positive strain curves (Figure 2) of all LA segmental components in 4CH apical view after setting adjusting the reference frame to coincide with the onset of the QRS.

Results

Figure 3 shows a time course of reservoir LA strain and left intra-atrial MD in patients with paroxysmal AF undergoing the First-CA (3A) versus the Redo-CA (3B), and in patients with long-standing persistent AF (3C). At 1-day pre-ablation, patients with long-standing persistent AF showed significantly lower reservoir strain of both atria and higher left intra-atrial MD as compared with both paroxysmal AF groups and controls (all p < 0.01). The Redo-CA versus the First-CA group showed significantly lower LA reservoir strain (p < 0.01) while left intra-atrial MD was similar. RA reservoir strain and inter-atrial MD was similar between groups with paroxysmal AF. At 1-day post-ablation, we observed a significant deterioration of reservoir LA strain and left intra-atrial MD only in the First-CA group. After 3- month follow-up, left intra-atrial synchrony was significantly improved compared with pre-ablation in both groups of paroxysmal AF undergoing the first CA and long-standing persistent AF (p < 0.05). The reservoir LA strain showed partial recovery to pre-ablation values in paroxysmal AF undergoing first-CA while it showed a continuous improvement in long-standing persistent AF. In contrast, patients with paroxysmal AF undergoing redo-CA did not show significant improvement in any of these indices. Inter-atrial MD and RA strain did not show significant improvement in either group.

Conclusion

Atrial strain and MD shows distinct behavior in patients with different sub-types of AF post CA. Atrial MD may provide a complimentary information to strain when assessing LA function.

Abstract 554 Figure.

P660The effect of hypertension and metabolic syndrome on left atrial function in patients with paroxysmal atrial fibrillation undergoing catheter ablation

Background

Hypertension and metabolic risk factors are associated with increased risk of atrial fibrillation (AF) and heart failure. Previous studies assessing the efficacy of catheter ablation in patients with metabolic syndrome have shown conflicting data.

Purpose

We thought to assess the impact of hypertension and other metabolic risk factors on left atrial (LA) phasic function in patients with paroxysmal AF undergoing the first catheter ablation.

Methods

We prospectively enrolled 112 consecutive patients (age: 63±21 years; 32% female) with symptomatic paroxysmal AF and preserved left ventricular ejection fraction (≥50%) undergoing the first catheter ablation during sinus rhythm, and 23 healthy controls. Patients with valvular AF or in AF at the time of ablation were excluded. All patients underwent comprehensive echocardiography at one day pre and at one day post ablation, and after three months. The LA reservoir, conduit and contractile strain and strain rate (SR) were assessed using the two-dimensional speckle tracking echocardiography as average of segmental values in apical views.

Results

A total of 51 (45.5%) patients had history of treated hypertension while 61 (54.5%) patients had normal arterial blood pressure, and 27 (24.1%) patients of hypertensive group and 17 (15.1%) patients of normotensive group have dyslipidemia and/or diabetes. All groups of patients had been adjusted by age and sex. Pre-ablation, hypertensive patients with metabolic risk factors showed significantly lower magnitude of reservoir and contractile strain and SR compared with other groups of patients (all p<0.05). Hypertensive patients compared with normotensive patients had significantly increase in LA volume index (39±1% vs. 34±7%, p: 0.01) and decrease in LA emptying fraction (49.5±11% vs. 54.8±9.8%, p: 0.02). Post-ablation, LA strain and SR significantly decreased in all patients regardless of the history of hypertension or other metabolic risk factors (all p<0.05). At three-month follow-up, LA strain and SR showed almost complete recovery to pre-ablation values in both groups of patients. Yet, LA function in groups of patients with metabolic risk factors remained lower compared with individuals without risk factors. Of note, hypertensive individuals showed similar improvement of LA contractile function to normotensive patients (p: 0.4) but LA reservoir function remained to be lower (p<0.05) (figure 1,2). The intra- and the inter-observer variability for the LAS and LASR assessment were below 5% and significantly lower (p<0.05) than that of the conventional LA indices.

Conclusion

Both reservoir and contractile LA strain are simultaneously affected by dyslipidemia and/or diabetes. LA reservoir function is affected earlier in hypertensive patients than contractile function. Reservoir LA strain appears to be the most useful parameter to monitor LA function in hypertensive patients with/without metabolic risk factors.

P2451Patterns of left atrial structural and functional remodeling after catheter ablation in paroxysmal and long-standing persistent atrial fibrillation

Background

Both atrial fibrillation (AF) and catheter ablation (CA) may be associated with changes in left atrial (LA) structure and function. However, the data describing acute and short-term effects of CA on LA contractile function in different sub-types of AF are scarce.

Purpose

First, to describe patterns of LA structural and functional remodeling in patients with paroxysmal AF (PAF) or long-standing persistent AF (LSPAF) undergoing first or redo CA. Second, to assess clinical feasibility of LA strain and strain rate (SR) to monitor effect of AF and CA on LA contractile function.

Methods

We prospectively enrolled 138 consecutive patients (age: 63±21 years, 32% females) with PAF undergoing first (81%) or redo (19%) CA during sinus rhythm, and 20 individuals (age: 66±23 years, 20% females) with LSPAF undergoing first CA during AF. All patients were symptomatic and preserved (≥50%) left ventricular ejection fraction. Control group consisted of 23 healthy controls. All patients underwent comprehensive echocardiography one day pre-CA and post-CA, and at 3 month follow-up. The LA reservoir, conduit and contractile longitudinal strain (LAS) and LASR were assessed using 2D speckle tracking echocardiography as average of segmental values in apical views.

Results

A total of 14 (9%) patients had insufficient image quality for LA assessment and were excluded (feasibility: 91%). Pre-CA, patients with LSPAF showed the largest left atrial volume index (LAVI) (45±14 ml/m2), followed by PAF (35±8 ml/m2) and controls (24±10 ml/m2) (p<0.001). The lowest reservoir and contractile LAS was observed in patients with LSPAF (12±5% and 0%), followed by PAF undergoing redo CA (22±7% and 9±4%), versus first CA (27±8% and 13±4%) and controls (37±7% and 16±4%) (p<0.001). LASR followed similar trend. Post-CA, we observed acute increase of LAVI in all groups (figure 1). Reservoir and contractile LAS and LASR decreased only in patients with PAF who underwent first CA. In contrast, it remained unchanged in individuals with PAF who had redo CA or even increased in subjects with LSPAF (figure 2). At 3 month follow-up, LAVI was significantly reduced compared with baseline in all groups of patients with AF (p<0.01). In contrast, LAS and LASR did not show uniform improvement in all AF groups and on average they remained significantly lower compared with controls (p<0.01). The lowest LAS and LASR values were observed in patients with PAF who underwent redo CA (no improvement from baseline) and in patients with LSPAF (significant improvement versus baseline) (figure 2). Patients with PAF who had the first CA showed higher LAS and LASR compared with other two AF groups (p<0.01) but still significantly lower than controls (p<0.01).

Conclusion

Different sub-types of AF show different patterns of LA structural and functional remodeling after CA. Both reservoir and contractile LAS appear highly feasible and reproducible to monitor LA contractile function in this clinical setting.

Spinal epidural abscess

In a retrospective study, 68 patients with Spinal Epidural Abscess (SEA) were reviewed. Of these, 66% had different predisposing factors such as staphylococcal skin infections, surgical procedures, rachicentesis, trauma, spondilodiscitis. Abscess had a lumbar region location in 53% of cases. Staphylococcus aureus was the most frequent etiological agent (81%). The overall rate of mortality in SEA patients was 13.2%.