Topological Learning Approach to Characterizing Biological Membranes.

Biological membranes play key roles in cellular compartmentalization, structure, and its signaling pathways. At varying temperatures, individual membrane lipids sample from different configurations, a process that frequently leads to higher-order phase behavior and phenomena. Here, we present a persistent homology (PH)-based method for quantifying the structural features of individual and bulk lipids, providing local and contextual information on lipid tail organization. Our method leverages the mathematical machinery of algebraic topology and machine learning to infer temperature-dependent structural information on lipids from static coordinates. To train our model, we generated multiple molecular dynamics trajectories of dipalmitoyl-phosphatidylcholine membranes at varying temperatures. A fingerprint was then constructed for each set of lipid coordinates by PH filtration, in which interaction spheres were grown around the lipid atoms while tracking their intersections. The sphere filtration formed a simplicial complex that captures enduring key topological features of the configuration landscape using homology, yielding persistence data. Following fingerprint extraction for physiologically relevant temperatures, the persistence data were used to train an attention-based neural network for assignment of effective temperature values to selected membrane regions. Our persistence homology-based method captures the local structural effects, via effective temperature, of lipids adjacent to other membrane constituents, e.g., sterols and proteins. This topological learning approach can predict lipid effective temperatures from static coordinates across multiple spatial resolutions. The tool, called MembTDA, can be accessed at https://github.com/hyunp2/Memb-TDA.

Influence of H+, OH- and salts on hydrophobic self-assembly.

In spite of the ubiquity of acid/base ions and salts in biological systems, their influence on hydrophobic self-assembly remains an open question. Here we use a combined experimental and theoretical strategy to quantify the influence of H+ and OH-, as well as salts containing Li+, Na+, Cl- and Br-, on the hydrophobic self-assembly of micelles composed of neutral oily 1,2-hexanediol surfactants. The distributions of aggregate sizes, both below and above the critical micelle concentration (CMC), are determined using Raman multivariate curve resolution (Raman-MCR) spectroscopy to quantify the multi-aggregation chemical potential surface (MCPS) that drives self-assembly. The results reveal that ions have little influence on the formation of hydrophobic contact dimers but can significantly drive high-order self assembly. Moreover, the hydration-shells of oily solutes are found to expel the above salt ions and OH-, but to attract H+, with wide-ranging implications.

A Mini Literature Review of Probiotics: Transforming Gastrointestinal Health Through Evidence-Based Insights.

As our understanding of the intricate interaction between gut bacteria and human health continues to expand, so too has interest in the ability of probiotics to manage gut microbiota and confer multiple health benefits to the host. The mini literature review focuses on the expanding potential of the use of probiotics in GI health, with a focus on probiotics' potential therapeutic advantages in a variety of gastrointestinal (GI) illnesses. Probiotics play a significant role in managing diarrhea and symptoms of irritable bowel syndrome with diarrhea (IBS-D) by modulating gut microbial communities. Specific probiotic strains have been found to reduce the abundance of harmful bacteria, regulate inflammatory markers like interleukin 6, and improve GI symptoms such as abdominal discomfort and stool consistency. Additionally, probiotic blends have shown potential for preventing GI infections and alleviating GI pain in IBS-D patients. Studies have demonstrated that certain multi-strain probiotics, including Bifidobacterium and Lactobacillus species, can significantly increase the frequency of bowel movements and reduce the proportion of individuals experiencing constipation. It has also been found that probiotic supplementation may reduce the incidence of postoperative complications and mortality, particularly in patients undergoing colorectal adenocarcinoma surgery. Additionally, probiotics have been associated with decreased levels of pro-inflammatory cytokines and improved clinical outcomes in patients with colorectal cancer. Furthermore, probiotics have been associated with enhanced digestive tolerance, reduced GI inflammation, and prolonged clinical remission in certain UC patients. Studies have also shown that probiotics, administered either directly to infants or pregnant women during the perinatal stage, can alleviate symptoms such as inconsolable crying and irritation associated with infant colic, improve bowel movement frequency in cases of functional constipation, and enhance overall conditions in premature infants, including reducing regurgitation and improving feeding tolerance. The review addresses both encouraging results and challenges with probiotic therapy, while also arguing for more studies to elucidate underlying mechanisms and enhance therapeutic techniques. As we traverse the complex field of probiotic therapy in the treatment of GI illnesses, researchers, physicians, and other healthcare professionals can benefit from the informative information provided by this study.

Proprioception and Control of a Soft Pneumatic Actuator Made of a Self-Healable Hydrogel.

The current evolutionary trends in soft robotics try to exploit the capacities of smart materials to achieve compact robotics designs with embodied intelligence. In this way, the number of elements that compose the soft robot can be reduced, as the smart material can cover different aspects (e.g., structure and sensorization) all in one. This work follows this tendency and presents a custom-designed hydrogel that exhibits two smart features, self-healing and ionic conductivity, used to build a pneumatic actuator. The self-healing capability provides the actuator's structure with the ability to self-repair from damages (e.g., punctures or cuts), an important quality to prolong the life cycle of the actuator. The ionic conductivity enables the actuator's proprioception: the structure itself serves as a curvature sensor. The behavior of this proprioceptive curvature sensor is analyzed in this work, studying its linearity, stability, and performance after a self-healing process. This sensor is also proposed as feedback in a closed-loop scheme to automatically control the actuator's curvature. A proportional-integral-derivative controller is designed based on an empirical model of the actuator's dynamics, and then validated in experimental tests, proving the proprioceptive sensor as proper feedback. These control tests are performed over undamaged and self-healed actuators, thus demonstrating all the capabilities of our soft material.

Click-Capable Phenanthriplatin Derivatives as Tools to Study Pt(II)-Induced Nucleolar Stress.

It is well established that oxaliplatin, one of the three Pt(II) anticancer drugs approved worldwide, and phenanthriplatin, an important preclinical monofunctional Pt(II) anticancer drug, possess a different mode of action from that of cisplatin and carboplatin, namely, the induction of nucleolar stress. The exact mechanisms that lead to Pt-induced nucleolar stress are, however, still poorly understood. As such, studies aimed at better understanding the biological targets of both oxaliplatin and phenanthriplatin are urgently needed to expand our understanding of Pt-induced nucleolar stress and guide the future design of Pt chemotherapeutics. One approach that has seen great success in the past is the use of Pt-click complexes to study the biological targets of Pt drugs. Herein, we report the synthesis and characterization of the first examples of click-capable phenanthriplatin complexes. Furthermore, through monitoring the relocalization of nucleolar proteins, RNA transcription levels, and DNA damage repair biomarker γH2AX, and by investigating their in vitro cytotoxicity, we show that these complexes successfully mimic the cellular responses observed for phenanthriplatin treatment in the same experiments. The click-capable phenanthriplatin derivatives described here expand the existing library of Pt-click complexes. Significantly they are suitable for studying nucleolar stress mechanisms and further elucidating the biological targets of Pt complexes.

Capturing CO2 in Quadrupolar Binding Pockets: Broadband Microwave Spectroscopy of Pyrimidine-(CO2)n, n = 1,2.

Pyrimidine has two in-plane CH(δ+)/N̈(δ-)/CH(δ+) binding sites that are complementary to the (δ-/2δ+/δ-) quadrupole moment of CO2. We recorded broadband microwave spectra over the 7.5-17.5 GHz range for pyrimidine-(CO2)n with n = 1 and 2 formed in a supersonic expansion. Based on fits of the rotational transitions, including nuclear hyperfine splitting due to the two 14N nuclei, we have assigned 313 hyperfine components across 105 rotational transitions for the n = 1 complex and 208 hyperfine components across 105 rotational transitions for the n = 2 complex. The pyrimidine-CO2 complex is planar, with CO2 occupying one of the quadrupolar binding sites, forming a structure in which the CO2 is stabilized in the plane by interactions with the C-H hydrogens adjacent to the nitrogen atom. This structure is closely analogous to that of the pyridine-CO2 complex studied previously by (Doran, J. L. J. Mol. Struct. 2012, 1019, 191-195). The fit to the n = 2 cluster gives rotational constants consistent with a planar cluster of C2v symmetry in which the second CO2 molecule binds in the second quadrupolar binding pocket on the opposite side of the ring. The calculated total binding energy in pyrimidine-CO2 is -13.7 kJ mol-1, including corrections for basis set superposition error and zero-point energy, at the CCSD(T)/ 6-311++G(3df,2p) level, while that in pyrimidine-(CO2)2 is almost exactly double that size, indicating little interaction between the two CO2 molecules in the two binding sites. The enthalpy, entropy, and free energy of binding are also calculated at 300 K within the harmonic oscillator/rigid-rotor model. This model is shown to lack quantitative accuracy when it is applied to the formation of weakly bound complexes.

Prevalence of hepatic steatosis and fibrosis in apparently healthy airline pilots: A transient elastography study.

Background and Aim: Airline pilots (APs) are often characterized by a sedentary lifestyle, predisposing them to adverse cardiometabolic consequences. In this cross-sectional study, we used transient elastography (TE) to investigate the prevalence of hepatic steatosis and fibrosis among apparently healthy APs. Materials and Methods: The study cohort consisted of 137 male APs of Caucasian descent who voluntarily underwent TE. To evaluate the extent and severity of hepatic steatosis and fibrosis, we employed established cutoff values for the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM). Results: Of the APs, 34 (24.8%) were diagnosed with TE-defined steatosis. Specifically, 25 APs (18.2%) exhibited mild steatosis, 6 (4.4%) moderate steatosis, and 3 (2.2%) severe steatosis. The majority of participants (80 APs or 58.4%) showed no signs of liver fibrosis based on LSM values. However, 49 APs (35.8%) were diagnosed with mild fibrosis (F1), 7 (5.1%) with significant fibrosis (F2), and one (0.7%) with advanced fibrosis (F3). None of the pilots had F4 (cirrhosis). In multivariable linear regression analysis, BMI was the sole independent predictor of both CAP (ß=0.34, p<0.001) and LSM (ß=0.41, p<0.001) values in our sample of male APs. Conclusion: TE is a straightforward and convenient non-invasive method for detecting hepatic steatosis and fibrosis in high-risk occupational groups such as APs.

Topological Learning Approach to Characterizing Biological Membranes.

Biological membranes play key roles in cellular compartmentalization, structure, and its signaling pathways. At varying temperatures, individual membrane lipids sample from different configurations, a process that frequently leads to higher-order phase behavior and phenomena. Here we present a persistent homology-based method for quantifying the structural features of individual and bulk lipids, providing local and contextual information on lipid tail organization. Our method leverages the mathematical machinery of algebraic topology and machine learning to infer temperature-dependent structural information of lipids from static coordinates. To train our model, we generated multiple molecular dynamics trajectories of DPPC membranes at varying temperatures. A fingerprint was then constructed for each set of lipid coordinates by a persistent homology filtration, in which interactions spheres were grown around the lipid atoms while tracking their intersections. The sphere filtration formed a simplicial complex that captures enduring key topological features of the configuration landscape, using homology, yielding persistence data. Following fingerprint extraction for physiologically relevant temperatures, the persistence data were used to train an attention-based neural network for assignment of effective temperature values to selected membrane regions. Our persistence homology-based method captures the local structural effects, via effective temperature, of lipids adjacent to other membrane constituents, e.g. sterols and proteins. This topological learning approach can predict lipid effective temperatures from static coordinates across multiple spatial resolutions. The tool, called MembTDA, can be accessed at https://github.com/hyunp2/Memb-TDA.

Quantifying the Nearly Random Microheterogeneity of Aqueous tert-Butyl Alcohol Solutions Using Vibrational Spectroscopy.

The microheterogeneous structure of aqueous tert-butyl alcohol (TBA) solutions is quantified by combining experimental, simulations, and theoretical results. Experimental Raman multivariate curve resolution (Raman-MCR) C-H frequency shift measurements are compared with predictions obtained using combined quantum mechanical and effective fragment potential (QM/EFP) calculations, as well as with molecular dynamics (MD), random mixture (RM), and finite lattice (FL) predictions. The results indicate that the microheterogeneous aggregation in aqueous TBA solutions is slightly less than that predicted by MD simulations performed using either CHARMM generalized force field (CGenFF) or optimized parameters for liquid simulations all atom (OPLS-AA) force fields but slightly more than that in a self-avoiding RM of TBA-like molecules. The results imply that the onset of microheterogeneity in aqueous solutions occurs when solute contact free energies are about an order of magnitude smaller than thermal fluctuations, thus suggesting a fundamental bound of relevance to biological self-assembly.

Tuning sterol extraction kinetics yields a renal-sparing polyene antifungal.

Decades of previous efforts to develop renal-sparing polyene antifungals were misguided by the classic membrane permeabilization model1. Recently, the clinically vital but also highly renal-toxic small-molecule natural product amphotericin B was instead found to kill fungi primarily by forming extramembraneous sponge-like aggregates that extract ergosterol from lipid bilayers2-6. Here we show that rapid and selective extraction of fungal ergosterol can yield potent and renal-sparing polyene antifungals. Cholesterol extraction was found to drive the toxicity of amphotericin B to human renal cells. Our examination of high-resolution structures of amphotericin B sponges in sterol-free and sterol-bound states guided us to a promising structural derivative that does not bind cholesterol and is thus renal sparing. This derivative was also less potent because it extracts ergosterol more slowly. Selective acceleration of ergosterol extraction with a second structural modification yielded a new polyene, AM-2-19, that is renal sparing in mice and primary human renal cells, potent against hundreds of pathogenic fungal strains, resistance evasive following serial passage in vitro and highly efficacious in animal models of invasive fungal infections. Thus, rational tuning of the dynamics of interactions between small molecules may lead to better treatments for fungal infections that still kill millions of people annually7,8 and potentially other resistance-evasive antimicrobials, including those that have recently been shown to operate through supramolecular structures that target specific lipids9.

Sugar responsiveness could determine foraging patterns in yellowjackets.

Sympatric-related species often exhibit resource partitioning. This can occur through different mechanisms, such as behavioral, morphological, and sensory variations, leading to qualitative, temporal, or spatial differences in resource exploitation, such as consuming different types of food. Sensory-based niche partitioning could be the underlying mechanism through which closely related species effectively reduce niche overlap. Here we ask whether variations in sensory responses to carbohydrates could reflect differences in the foraging patterns of two Vespula species present in Patagonia. For this, we established (i) the response thresholds toward carbohydrate solutions of foraging V. germanica and V. vulgaris in the laboratory, (ii) the sugar concentration of foraged carbohydrates in the field, and (iii) possible effects of incoming sugar concentration and performance at individual and colony levels. Results indicate a higher sucrose response threshold in V. germanica than V. vulgaris. Field results indicate that higher carbohydrate concentrations foraged by V. germanica, with 57% of V. germanica foragers returning with concentrations above 50% w/w, while only 23% of V. vulgaris foragers did so. These differences in sucrose sensitivity and foraging patterns positively correlate with colony size, irrespective of the species. Our results suggest that competition could be reduced in these closely related invasive social wasp species through sensory differences in their sugar perception levels, which would lead to them foraging different carbohydrate sources. This study suggests that sensory niche partitioning could promote species coexistence in these social wasps.

Impact of Job Types on Plasma Neurotrophins Levels: A Preliminary Study in Airline Pilots, Construction Workers, and Fitness Instructors.

BACKGROUND: Neurotrophins (NTs) encompass a group of closely associated proteins regulating various aspects of neuronal growth and survival. The potential association between work-related factors and the levels of circulating NTs has not been extensively examined. In this preliminary investigation, we evaluated plasma concentrations of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4) in a cohort of healthy individuals from three distinct professional categories, each with unique work environments and lifestyle factors. METHODS: The study involved 60 men from three professional fields: airline pilots, construction laborers, and fitness trainers (20 participants per category) recruited during routine occupational health appointments. Plasma levels of NTs were measured using commercially available immunoassays and compared in the three professional groups. RESULTS: Among the professions studied, fitness instructors displayed the highest concentrations of BDNF and NGF, with airline pilots ranking second, and construction workers showing the lowest levels. Significantly decreased NT-3 levels were observed in airline pilots compared to fitness instructors and construction workers, but no differences were found between the latter two occupations. NT-4 levels were similar across all three occupational groups. CONCLUSIONS: Our pilot results suggest that plasma concentrations of NTs, which are involved in various aspects of neuronal and cognitive functioning, may display significant differences among healthy individuals depending on their occupation. These observations warrant additional research to explore potential implications for the field of occupational medicine.

Comparison of click-capable oxaliplatin and cisplatin derivatives to better understand Pt(ii)-induced nucleolar stress.

Pt(ii) chemotherapeutic complexes have been used as predominant anticancer drugs for nearly fifty years. Currently there are three FDA-approved chemotherapeutic Pt(ii) complexes: cisplatin, carboplatin, and oxaliplatin. Until recently, it was believed that all three complexes induced cellular apoptosis through the DNA damage response pathway. Studies within the last decade, however, suggest that oxaliplatin may instead induce cell death through a unique nucleolar stress pathway. Pt(ii)-induced nucleolar stress is not well understood and further investigation of this pathway may provide both basic knowledge about nucleolar stress as well as insight for more tunable Pt(ii) chemotherapeutics. Through a previous structure-function analysis, it was determined that nucleolar stress induction is highly sensitive to modifications at the 4-position of the 1,2-diaminocyclohexane (DACH) ring of oxaliplatin. Specifically, more flexible and less rigid substituents (methyl, ethyl, propyl) induce nucleolar stress, while more rigid and bulkier substituents (isopropyl, acetamide) do not. These findings suggest that a click-capable functional group can be installed at the 4-position of the DACH ring while still inducing nucleolar stress. Herein, we report novel click-capable azide-modified oxaliplatin mimics that cause nucleolar stress. Through NPM1 relocalization, fibrillarin redistribution, and γH2AX studies, key differences have been identified between previously studied click-capable cisplatin mimics and these novel click-capable oxaliplatin mimics. These complexes provide new tools to identify cellular targets and localization through post-treatment Cu-catalyzed azide-alkyne cycloaddition and may help to better understand Pt(ii)-induced nucleolar stress. To our knowledge, these are the first reported oxaliplatin mimics to include an azide handle, and cis-[(1R,2R,4S) 4-methylazido-1,2-cyclohexanediamine]dichlorido platinum(ii) is the first azide-functionalized oxaliplatin derivative to induce nucleolar stress.

Mild Depressive Symptoms in Airline Pilots Associated With Impaired Executive Functions.

INTRODUCTION: While significant efforts have been made to understand the influence of depression-related impairments on executive functioning within the general population, the specific impact on airline pilots remains largely unexplored. Considering the crucial role that cognitive abilities play in the realm of aircraft piloting, it is imperative to probe into the potential repercussions of depressive symptoms on executive functions (EFs) among this professional cohort. OBJECTIVES:  This study aims to explore the associations between depressive symptoms and EFs in a convenience sample of airline pilots. METHODS:  Male airline pilots (n = 100) underwent the Beck Depression Inventory II (BDI-II) to gauge both the presence and intensity of depressive symptoms. The Stroop Color and Word Test (SCWT), the Digit Span Task (DST), and the Wisconsin Card Sorting Test (WCST) were used to assess EFs. RESULTS:  Of the entire sample of pilots, 88% (n = 88) demonstrated minimal depressive symptoms with a BDI-II score ranging from 0 to 13. The remaining 12% (n = 12) exhibited mild depression, with scores between 14 and 19. Pilots suffering from mild depression demonstrated prolonged color and word times and a higher time interference (TI) score on the SCWT. Moreover, these individuals exhibited lower scores on the DST across both the forward digit span (FDS) and backward digit span (BDS) subtests. Finally, the presence of mild depression correlated with an increased number of total errors, encompassing both perseverative and non-perseverative errors, in the WCST. After adjusting for potential confounding variables, we found an independent association between BDI-II scores and total errors in the WCST. CONCLUSION: Our research points to substantial differences in EFs between airline pilots demonstrating mild depression and those exhibiting minimal depressive symptoms. This information can catalyze heightened consciousness about the psychological welfare of pilots.

Impact of different job types on serum cytokine levels in apparently healthy individuals: A comparative study among airline pilots, construction workers, and fitness instructors.

BACKGROUND: The impact of occupational factors on serum cytokine concentrations has not been extensively explored. In this preliminary investigation, we measured the amounts of 12 cytokines in the serum of healthy individuals, comparing three diverse professional categories (aviation pilots, building laborers, and exercise trainers) with distinct work settings and lifestyle factors. METHODS: The study sample comprised 60 men from three distinct professional fields - airline pilots, construction laborers, and fitness trainers (20 participants per category) - who were enlisted during regular outpatient occupational health appointments. Serum levels of interleukin (IL)-1ß, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-17, tumor necrosis factor (TNF)-α, interferon (IFN)-α, and IFN-γ were measured on a Luminex® platform using a specific kit. Cytokine levels were compared among the three professional groups to determine any significant differences. RESULTS: Among the three occupational groups, fitness instructors demonstrated elevated IL-4 concentrations in comparison to both airline pilots and construction laborers, with no significant difference between the latter two professions. Additionally, a stepwise increase in IL-6 levels was identified, commencing with fitness instructors presenting the lowest quantities, succeeded by construction workers, and culminating with airline pilots, who displayed the most elevated concentrations. CONCLUSION: Serum cytokine levels in healthy individuals can exhibit variations based on their occupation. Given the unfavorable cytokine profile detected in airline pilots, it is crucial for the aviation sector to tackle potential health concerns within their employees.

Development and evaluation of Microbe Finder (MiFi)®: a novel in silico diagnostic platform for pathogen detection from metagenomic data.

Introduction. With expanding demand for diagnostics, newer methodologies are needed for faster, user-friendly and multiplexed pathogen detection. Metagenome-based diagnostics offer potential solutions to address these needs as sequencing technologies have become affordable. However, the diagnostic utility of sequencing technologies is currently limited since analysis of the large amounts of data generated, are either computationally expensive or carry lower sensitivity and specificity for pathogen detection.Hypothesis/Gap Statement. There is a need for novel, user friendly, and computationally inexpensive platforms for metagenome sequence analysis for diagnostic applications.Methods. In this study, we report the use of MiFi® (Microbe Finder), a computationally inexpensive algorithm with a user-friendly online interface, for accurate, rapid and multiplexed pathogen detection from metagenome sequence data. Detection is accomplished based on identification of signature genomic sequence segments of the target pathogen in metagenome sequence data. In this study we used bovine respiratory disease (BRD) complex as a model.Results and Conclusions. Using MiFi®, multiple target bacteria and a DNA virus were successfully detected in a multiplex format from metagenome sequences acquired from bovine lung tissue. Overall, 51 clinical samples were assessed and MiFi® showed 100 % analytical specificity and varying levels of analytical sensitivity (62.5 %-100 %) when compared with other traditional pathogen detection techniques, such as PCR. Consistent detection of bacteria was possible from lung samples artificially spiked with 109-104 c.f.u. of Mannheimia haemolytica.

Proximal Instructions for Use Violations in Elective Endovascular Aneurysm Repair in the Vascular Quality Initiative: Retrospective Analysis.

BACKGROUND: Endovascular aneurysm repair (EVAR) is often attempted in patients with marginal anatomy. These patients' midterm outcomes are available in the Vascular Quality Initiative for analysis. STUDY DESIGN: Retrospective analysis of prospectively collected data in the Vascular Quality Initiative from patients who underwent elective infrarenal EVAR between 2011 and 2018. Each EVAR was identified as either on- or off-instructions for use (IFU) based on aortic neck criteria. Multivariable logistic regression models were used to assess associations between aneurysm sac enlargement, reintervention, and type Ia endoleak with IFU status. Kaplan-Meier time-to-event models estimated reintervention, aneurysm sac enlargement, and overall survival. RESULTS: We identified 5,488 patients with at least 1 follow-up recorded. Those treated off-IFU included 1,236 patients ([23%] mean follow-up 401 days) compared with 4,252 (77%) treated on-IFU (mean follow-up 406 days). There was no evidence of significant differences in crude 30-day survival (96% vs 97%; p = 0.28) or estimated 2-year survival (97% vs 97%; log-rank p = 0.28). Crude type Ia endoleak frequency was greater in patients treated off IFU (2% vs 1%; p = 0.03). Off-IFU EVAR was associated with type Ia endoleak on multivariable regression model (odds ratio 1.84 [95% CI 1.23 to 2.76]; p = 0.003). Patients treated off IFU vs on IFU experienced had increased risk of reintervention within 2 years (7% vs 5%; log-rank p = 0.02), a finding consistent with results from the Cox modeling (hazard ratio 1.38 [95% CI 1.06 to 1.81]; p = 0.02). CONCLUSIONS: Patients treated off IFU were at greater risk for type Ia endoleak and reintervention, although they had similar 2-year survival compared with those treated on IFU. Patients with anatomy outside IFU should be considered for open surgery or complex endovascular repair to reduce the probability for revision.