ALDH4A1 is an atherosclerosis auto-antigen targeted by protective antibodies.

Cardiovascular disease (CVD) is the leading cause of mortality in the world, with most CVD-related deaths resulting from myocardial infarction or stroke. The main underlying cause of thrombosis and cardiovascular events is atherosclerosis, an inflammatory disease that can remain asymptomatic for long periods. There is an urgent need for therapeutic and diagnostic options in this area. Atherosclerotic plaques contain autoantibodies1,2, and there is a connection between atherosclerosis and autoimmunity3. However, the immunogenic trigger and the effects of the autoantibody response during atherosclerosis are not well understood3-5. Here we performed high-throughput single-cell analysis of the atherosclerosis-associated antibody repertoire. Antibody gene sequencing of more than 1,700 B cells from atherogenic Ldlr-/- and control mice identified 56 antibodies expressed by in-vivo-expanded clones of B lymphocytes in the context of atherosclerosis. One-third of the expanded antibodies were reactive against atherosclerotic plaques, indicating that various antigens in the lesion can trigger antibody responses. Deep proteomics analysis identified ALDH4A1, a mitochondrial dehydrogenase involved in proline metabolism, as a target antigen of one of these autoantibodies, A12. ALDH4A1 distribution is altered during atherosclerosis, and circulating ALDH4A1 is increased in mice and humans with atherosclerosis, supporting the potential use of ALDH4A1 as a disease biomarker. Infusion of A12 antibodies into Ldlr-/- mice delayed plaque formation and reduced circulating free cholesterol and LDL, suggesting that anti-ALDH4A1 antibodies can protect against atherosclerosis progression and might have therapeutic potential in CVD.

Common and specific proteins and pathways in heart and cerebral ischemia.

OBJECTIVE: To understand the similarities and differences between acute ischemic stroke and acute myocardial infarction (AMI) to help in the development of specific or common treatment strategies. METHODS: Using an aptamer-based proteomic array, we measured and compared 1310 circulating proteins in the blood of 40 patients with AIS, 9 patients with AMI, and 31 healthy controls. Pathway enrichment analysis was performed using GSEA and g:profiler. RESULTS: Ninety-four proteins were differentially expressed in AIS, and 284 were differentially expressed in AMI. Of these, 8 were specific to cerebral ischemia, and 197 were specific to myocardial infarction. Forty-two proteins were altered in both ischemia processes. Most altered pathways in AIS could be classified as immune response, cell cycle processing, molecular transport, or signaling. Pathways altered in AMI were mostly related to lipid metabolism and transport, highlighting cholesterol metabolic processes and estrogen signaling. In both types of ischemia, we found pathways related to metabolism, specifically purine metabolism, and signaling processes, such as TNF signaling or MAPK1/3. CONCLUSIONS: The present study revealed proteins and pathways that were specifically altered in cerebral ischemia, in cardiac ischemia, or in both diseases, providing information on the similarities and differences of ischemic conditions. The role of common and specific proteins and pathways should be explored in detail to find possible therapeutic targets.

Longitudinal dynamics of SARS-CoV-2-specific cellular and humoral immunity after natural infection or BNT162b2 vaccination.

The timing of the development of specific adaptive immunity after natural SARS-CoV-2 infection, and its relevance in clinical outcome, has not been characterized in depth. Description of the long-term maintenance of both cellular and humoral responses elicited by real-world anti-SARS-CoV-2 vaccination is still scarce. Here we aimed to understand the development of optimal protective responses after SARS-CoV-2 infection and vaccination. We performed an early, longitudinal study of S1-, M- and N-specific IFN-γ and IL-2 T cell immunity and anti-S total and neutralizing antibodies in 88 mild, moderate or severe acute COVID-19 patients. Moreover, SARS-CoV-2-specific adaptive immunity was also analysed in 234 COVID-19 recovered subjects, 28 uninfected BNT162b2-vaccinees and 30 uninfected healthy controls. Upon natural infection, cellular and humoral responses were early and coordinated in mild patients, while weak and inconsistent in severe patients. The S1-specific cellular response measured at hospital arrival was an independent predictive factor against severity. In COVID-19 recovered patients, four to seven months post-infection, cellular immunity was maintained but antibodies and neutralization capacity declined. Finally, a robust Th1-driven immune response was developed in uninfected BNT162b2-vaccinees. Three months post-vaccination, the cellular response was comparable, while the humoral response was consistently stronger, to that measured in COVID-19 recovered patients. Thus, measurement of both humoral and cellular responses provides information on prognosis and protection from infection, which may add value for individual and public health recommendations.

Small-bowel capsule endoscopy in patients with Meckel's diverticulum: clinical features, diagnostic workup, and findings. A European multicenter I-CARE study.

BACKGROUND AND AIMS: Meckel's diverticulum (MD) may remain silent or be associated with adverse events such as GI bleeding. The main aim of this study was to evaluate indicative small-bowel capsule endoscopy (SBCE) findings, and the secondary aim was to describe clinical presentation in patients with MD. METHODS: This retrospective European multicenter study included patients with MD undergoing SBCE from 2001 until July 2021. RESULTS: Sixty-nine patients with a confirmed MD were included. Median age was 32 years with a male-to-female ratio of approximately 3:1. GI bleeding or iron-deficiency anemia was present in nearly all patients. Mean hemoglobin was 7.63 ± 1.8 g/dL with a transfusion requirement of 52.2%. Typical capsule endoscopy (CE) findings were double lumen (n = 49 [71%]), visible entrance into the MD (n = 49 [71%]), mucosal webs (n = 30 [43.5%]), and bulges (n = 19 [27.5%]). Two or more of these findings were seen in 48 patients (69.6%). Ulcers were detected in 52.2% of patients (n = 36). In 63.8% of patients (n = 44), a combination of double lumen and visible entrance into the MD was evident, additionally revealing ulcers in 39.1% (n = 27). Mean percent SB (small bowel) transit time for the first indicative image of MD was 57% of the total SB transit time. CONCLUSIONS: Diagnosis of MD is rare and sometimes challenging, and a preoperative criterion standard does not exist. In SBCE, the most frequent findings were double-lumen sign and visible diverticular entrance, sometimes together with ulcers.

Cognitive disorders in patients with chronic kidney disease: Approaches to prevention and treatment.

BACKGROUND: Cognitive impairment is common in patients with chronic kidney disease (CKD), and early intervention may prevent the progression of this condition. METHODS: Here, we review interventions for the complications of CKD (anemia, secondary hyperparathyroidism, metabolic acidosis, harmful effects of dialysis, the accumulation of uremic toxins) and for prevention of vascular events, interventions that may potentially be protective against cognitive impairment. Furthermore, we discuss nonpharmacological and pharmacological methods to prevent cognitive impairment and/or minimize the latter's impact on CKD patients' daily lives. RESULTS: A particular attention on kidney function assessment is suggested during work-up for cognitive impairment. Different approaches are promising to reduce cognitive burden in patients with CKD but the availabe dedicated data are scarce. CONCLUSIONS: There is a need for studies assessing the effect of interventions on the cognitive function of patients with CKD.

Interplay between UNG and AID governs intratumoral heterogeneity in mature B cell lymphoma.

Most B cell lymphomas originate from B cells that have germinal center (GC) experience and bear chromosome translocations and numerous point mutations. GC B cells remodel their immunoglobulin (Ig) genes by somatic hypermutation (SHM) and class switch recombination (CSR) in their Ig genes. Activation Induced Deaminase (AID) initiates CSR and SHM by generating U:G mismatches on Ig DNA that can then be processed by Uracyl-N-glycosylase (UNG). AID promotes collateral damage in the form of chromosome translocations and off-target SHM, however, the exact contribution of AID activity to lymphoma generation and progression is not completely understood. Here we show using a conditional knock-in strategy that AID supra-activity alone is not sufficient to generate B cell transformation. In contrast, in the absence of UNG, AID supra-expression increases SHM and promotes lymphoma. Whole exome sequencing revealed that AID heavily contributes to lymphoma SHM, promoting subclonal variability and a wider range of oncogenic variants. Thus, our data provide direct evidence that UNG is a brake to AID-induced intratumoral heterogeneity and evolution of B cell lymphoma.

Genetic Architecture of Ischaemic Strokes after COVID-19 Shows Similarities with Large Vessel Strokes.

We aimed to analyse whether patients with ischaemic stroke (IS) occurring within eight days after the onset of COVID-19 (IS-COV) are associated with a specific aetiology of IS. We used SUPERGNOVA to identify genome regions that correlate between the IS-COV cohort (73 IS-COV cases vs. 701 population controls) and different aetiological subtypes. Polygenic risk scores (PRSs) for each subtype were generated and tested in the IS-COV cohort using PRSice-2 and PLINK to find genetic associations. Both analyses used the IS-COV cohort and GWAS from MEGASTROKE (67,162 stroke patients vs. 454,450 population controls), GIGASTROKE (110,182 vs. 1,503,898), and the NINDS Stroke Genetics Network (16,851 vs. 32,473). Three genomic regions were associated (p-value < 0.05) with large artery atherosclerosis (LAA) and cardioembolic stroke (CES). We found four loci targeting the genes PITX2 (rs10033464, IS-COV beta = 0.04, p-value = 2.3 × 10-2, se = 0.02), previously associated with CES, HS6ST1 (rs4662630, IS-COV beta = -0.04, p-value = 1.3 × 10-3, se = 0.01), TMEM132E (rs12941838 IS-COV beta = 0.05, p-value = 3.6 × 10-4, se = 0.01), and RFFL (rs797989 IS-COV beta = 0.03, p-value = 1.0 × 10-2, se = 0.01). A statistically significant PRS was observed for LAA. Our results suggest that IS-COV cases are genetically similar to LAA and CES subtypes. Larger cohorts are needed to assess if the genetic factors in IS-COV cases are shared with the general population or specific to viral infection.

Biological Age Acceleration Is Lower in Women With Ischemic Stroke Compared to Men.

BACKGROUND: Stroke onset in women occurs later in life compared with men. The underlying mechanisms of these differences have not been established. Epigenetic clocks, based on DNA methylation (DNAm) profiles, are the most accurate biological age estimate. Epigenetic age acceleration (EAA) measures indicate whether an individual is biologically younger or older than expected. Our aim was to analyze whether sexual dichotomy at age of stroke onset is conditioned by EAA. METHODS: We used 2 DNAm datasets from whole blood samples of case-control genetic studies of ischemic stroke (IS), a discovery cohort of 374 IS patients (N women=163, N men=211), from GRECOS (Genotyping Recurrence Risk of Stroke) and SEDMAN (Dabigatran Study in the Early Phase of Stroke, New Neuroimaging Markers and Biomarkers) studies and a replication cohort of 981 IS patients (N women=411, N men=570) from BASICMAR register. We compared chronological age, 2 DNAm-based biomarkers of aging and intrinsic and extrinsic epigenetic age acceleration EAA (IEAA and extrinsic EAA, respectively), in IS as well as in individual IS etiologic subtypes. Horvath and Hannum epigenetic clocks were used to assess the aging rate. A proteomic study using the SOMAScan multiplex assay was performed on 26 samples analyzing 1305 proteins. RESULTS: Women present lower Hannum-extrinsic EAA values, whereas men have higher Hannum-extrinsic EAA values (women=-0.64, men=1.24, P=1.34×10-2); the same tendency was observed in the second cohort (women=-0.57, men=0.79, P=0.02). These differences seemed to be specific to cardioembolic and undetermined stroke subtypes. Additionally, 42 blood protein levels were associated with Hannum-extrinsic EAA (P<0.05), belonging to the immune effector process (P=1.54×10-6) and platelet degranulation (P<8.74×10-6) pathways. CONCLUSIONS: This study shows that sex-specific underlying biological mechanisms associated with stroke onset could be due to differences in biological age acceleration between men and women.

Essential function for the GTPase TC21 in homeostatic antigen receptor signaling.

T cell antigen receptors (TCRs) and B cell antigen receptors (BCRs) transmit low-grade signals necessary for the survival and maintenance of mature cell pools. We show here that TC21, a small GTPase encoded by Rras2, interacted constitutively with both kinds of receptors. Expression of a dominant negative TC21 mutant in T cells produced a rapid decrease in cell viability, and Rras2(-/-) mice were lymphopenic, possibly as a result of diminished homeostatic proliferation and impaired T cell and B cell survival. In contrast, TC21 was overexpressed in several human lymphoid malignancies. Finally, the p110delta catalytic subunit of phosphatidylinositol-3-OH kinase (PI(3)K) was recruited to the TCR and BCR in a TC21-dependent way. Consequently, we propose TC21 directly links antigen receptors to PI(3)K-mediated survival pathways.

PATJ Low Frequency Variants Are Associated With Worse Ischemic Stroke Functional Outcome.

RATIONALE: Ischemic stroke is among the leading causes of adult disability. Part of the variability in functional outcome after stroke has been attributed to genetic factors but no locus has been consistently associated with stroke outcome. OBJECTIVE: Our aim was to identify genetic loci influencing the recovery process using accurate phenotyping to produce the largest GWAS (genome-wide association study) in ischemic stroke recovery to date. METHODS AND RESULTS: A 12-cohort, 2-phase (discovery-replication and joint) meta-analysis of GWAS included anterior-territory and previously independent ischemic stroke cases. Functional outcome was recorded using 3-month modified Rankin Scale. Analyses were adjusted for confounders such as discharge National Institutes of Health Stroke Scale. A gene-based burden test was performed. The discovery phase (n=1225) was followed by open (n=2482) and stringent joint-analyses (n=1791). Those cohorts with modified Rankin Scale recorded at time points other than 3-month or incomplete data on previous functional status were excluded in the stringent analyses. Novel variants in PATJ (Pals1-associated tight junction) gene were associated with worse functional outcome at 3-month after stroke. The top variant was rs76221407 (G allele, ß=0.40, P=1.70×10-9). CONCLUSIONS: Our results identify a set of common variants in PATJ gene associated with 3-month functional outcome at genome-wide significance level. Future studies should examine the role of PATJ in stroke recovery and consider stringent phenotyping to enrich the information captured to unveil additional stroke outcome loci.

Cognitive disorders in patients with chronic kidney disease: specificities of clinical assessment.

Neurocognitive disorders are frequent among chronic kidney disease (CKD) patients. Identifying and characterizing cognitive impairment (CI) can help to assess the ability of adherence to CKD risk reduction strategy, identify potentially reversible causes of cognitive decline, modify pharmacotherapy, educate the patient and caregiver and provide appropriate patient and caregiver support. Numerous factors are associated with the development and progression of CI in CKD patients and various conditions can influence the results of cognitive assessment in these patients. Here we review clinical warning signs that should lead to cognitive screening; conditions frequent in CKD at risk to interfere with cognitive testing or performance, including specificities of cognitive assessment in dialysis patients or after kidney transplantation; and available tests for screening and observed cognitive patterns in CKD patients.

Effect of late-onset epilepsy on cognitive functioning in patients with small vessel disease.

RATIONALE: Late-onset epilepsy (LOE) often has underlying cerebrovascular cause and has been associated with neurocognitive deficits and dementia. Nevertheless, the interplay between these factors has not been studied thus far. Hence, we conducted a retrospective cross-sectional study aimed to explore how unprovoked epileptic seizures along with vascular-related factors contribute to neurocognitive impairments in patients with cerebral small vessel disease. METHODS: Twenty-seven patients with LOE aged > 60 years with concomitant cerebral small vessel disease (cSVD) and a matched group of cSVD without epilepsy were cognitively assessed. Demographic, clinical, and vascular information were obtained and vascular burden score was calculated for each patient. Multiple linear regression models were used to explore the relationship between epilepsy and cognitive measures adjusting for demographic and vascular risk factors. RESULTS: Compared with cSVD, cSVD-LOE group showed a poorer performance on verbal memory measures, visuomotor tracking and speed processing and phonetic fluency. In the multiple regression analysis, the presence of epilepsy was found to be the major predictor for verbal memory dysfunction, specifically in verbal short recall (p = 0.008) and verbal learning (p < 0.001). No interactions between vascular burden and epilepsy were found. CONCLUSION: Patients who had cSVD with concurrent LOE showed poorer performance on memory function compared with patients with cSVD without epilepsy, and they showed a different cognitive profile from that typically manifested by patients with cSVD. The presence of epilepsy, but not seizure localization nor vascular burden, was the major contributor to the decrease in verbal memory.

T cell receptor internalization from the immunological synapse is mediated by TC21 and RhoG GTPase-dependent phagocytosis.

The immunological synapse (IS) serves a dual role for sustained T cell receptor (TCR) signaling and for TCR downregulation. TC21 (Rras2) is a RRas subfamily GTPase that constitutively associates with the TCR and is implicated in tonic TCR signaling by activating phosphatidylinositol 3-kinase. In this study, we demonstrate that TC21 both cotranslocates with the TCR to the IS and is necessary for TCR internalization from the IS through a mechanism dependent on RhoG, a small GTPase previously associated with phagocytosis. Indeed, we found that the TCR triggers T cells to phagocytose 1-6 µm beads through a TC21- and RhoG-dependent pathway. We further show that TC21 and RhoG are necessary for the TCR-promoted uptake of major histocompatibility complex (MHC) from antigen-presenting cells. Therefore, TC21 and RhoG dependence underlie the existence of a common phagocytic mechanism that drives TCR internalization from the IS together with its peptide-MHC ligand.

Matrix metalloproteinases and ADAMs in stroke.

Stroke is a leading cause of death and disability worldwide. However, after years of in-depth research, the pathophysiology of stroke is still not fully understood. Increasing evidence shows that matrix metalloproteinases (MMPs) and "a disintegrin and metalloproteinase" (ADAMs) participate in the neuro-inflammatory cascade that is triggered during stroke but also in recovery phases of the disease. This review covers the involvement of these proteins in brain injury following cerebral ischemia which has been widely studied in recent years, with efforts to modulate this group of proteins in neuroprotective therapies, together with their implication in neurorepair mechanisms. Moreover, the review also discusses the role of these proteins in specific forms of neurovascular disease, such as small vessel diseases and intracerebral hemorrhage. Finally, the potential use of MMPs and ADAMs as guiding biomarkers of brain injury and repair for decision-making in cases of stroke is also discussed.

Device-assisted enteroscopy training. A rapid review.

Device-assisted enteroscopy is currently lacking a validated training model, in contrast to the other major technique used for the study of the small bowel, namely capsule endoscopy. Training should be based on defining and achieving competency for the acquisition of the knowledge and skills required to perform enteroscopy in a safe and effective manner. The need for training is clear, since the technique is considered an advanced endoscopy form that requires maneuvers that differ from the usual ones that must be learned, in addition to specific equipment. Therefore, the ideal candidates for this training include professionals with accredited experience in therapeutic digestive endoscopy. Amongst the recommendations issued regarding device-assisted enteroscopy training, the estimation of small-bowel insertion depth and the choice of the examination route, whether oral or anal, should be highlighted. Learning curve descriptions have the limitation of being explorer-dependent with no consensus on the parameter that should be selected to establish a correct learning curve in enteroscopy. The most commonly used parameter is insertion depth. The few training models that have been proposed recommend using a highly useful tool, namely simulators and to start practicing under expert guidance. Based on the variability of published data, an experienced endoscopist may perform enteroscopy in a safe and effective manner after 5 to 35 training procedures. Although reaching the expert level requires prolonged clinical practice with exposure to the various disorders of the small bowel.

Quality indicators in enteroscopy. Enteroscopy procedure.

Within the project "Quality Indicators in Gastrointestinal Endoscopy," under the leadership of the Sociedad Española de Patología Digestiva (SEPD), our goal is to propose the procedures and the structure, process, and outcome indicators required for the application and assessment of quality in enteroscopy. To this end a search was performed for quality indicators in enteroscopy. Quality of evidence was measured by using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system, and classified as high, moderate, low, and very low. A total of 10 process indicators (one preprocedure, eight procedure, one postprocedure) were identified for enteroscopy, with appropriate indication and choice of most efficient route being most significant.

A comprehensive systematic review and meta-analysis of risk factors for rebleeding following device-assisted enteroscopy therapy of small-bowel vascular lesions.

INTRODUCTION: the aim of this study was to determine the risk factors for rebleeding following device-assisted enteroscopy therapy of small bowel vascular lesions. METHODS: this is a systematic review and meta-analysis. A literature search was performed from January 2003 to October 2019. All studies reporting on at least one risk factor for bleeding recurrence after endoscopic therapy of small bowel vascular lesions were included. A meta-analysis of those risk factors reported in at least three studies was performed to assess their association with rebleeding. The OR and 95 % CI were used for binary outcome data. Heterogeneity analysis was performed using the Tau and I2 index. If I2 > 20 %, potential sources of heterogeneity were identified by sensitivity analyses and a random-effect model was used. RESULTS: the search identified a total of 572 articles and 35 full-text records were assessed for eligibility after screening. Finally, eight studies that included 548 patients were selected. The overall median rebleeding rate was 38.5 % (range: 10.9-53.3 %) with a median follow-up of 24.5 months. Female sex (OR: 1.96, 95 % CI: 1.14-3.37, p = 0.01, I2 = 0 %), Osler-Weber syndrome (OR: 4.35, 95 % CI: 1.22-15.45, p = 0.02, I2 = 0 %) and cardiac disease (OR: 1.89, 95 % CI: 1.12-2.97, p = 0.005, I2: 0 %) were associated with rebleeding. According to the sensitivity analysis, overt bleeding (OR: 2.13, 95 % CI: 1.22-3.70, p = 0.007, I2 = 0 %), multiple lesions (OR: 4.57, 95 % CI: 2.04-10.22, p < 0.001, I2 = 0 %) and liver cirrhosis (OR: 2.61, 95 % CI: 1.11-6.13, p = 0.03, I2 = 0 %) were also predictors for rebleeding. CONCLUSIONS: patient characteristics and comorbidities should be considered for follow-up patient management after effective device-assisted endoscopic therapy, as they can predict rebleeding.

The rebleeding rate in patients evaluated for obscure gastrointestinal bleeding after negative small bowel findings by device assisted enteroscopy.

BACKGROUND: data on the long-term outcome of patients with obscure gastrointestinal bleeding (OGIB) with positive small bowel findings in capsule endoscopy but negative small bowel findings in device-assisted enteroscopy are scarce. OBJECTIVE: this study aimed to evaluate the rebleeding rate and time to rebleed in patients with no small bowel findings in enteroscopy, after a positive capsule endoscopy in the setting of OGIB. Baseline predictors for rebleeding were assessed. METHODS: a retrospective double-center study was performed, including patients with OGIB with positive findings by capsule endoscopy and negative small bowel findings by enteroscopy. RESULTS: thirty-five patients were included. Rebleeding occurred in 40 % of patients during a median follow-up of 27 months. Further evaluation in patients with a rebleed was performed in 85.7 %, leading to a final diagnosis in 78.6 %. The rebleeding rate increased progressively over time, from 17.2 % at one month to 54.4 % at four years. Overt bleeding at the time of the first episode was a predictor of rebleeding (p = 0.03) according to the multivariate analysis. This was 50 % at one year compared with 21.8 % in patients with occult bleeding on admission. CONCLUSIONS: in obscure gastrointestinal bleeding, long-term follow-up and further evaluation may be considered after a positive capsule endoscopy. Even if there are no small bowel findings by device-assisted enteroscopy. The rebleeding rate in our study was 40 %, mainly in the presence of an overt bleeding on admission.

Recurrent small-bowel bleeding from a Dieulafoy's lesion after combined endoscopic treatment.

INTRODUCTION: Dieulafoy's lesion of the small bowel is an uncommon cause of gastrointestinal (GI) bleeding that often recurs after endoscopic treatment. MATERIAL AND METHODS: we report an observational, descriptive, retrospective, single-center study in 15 patients with small bowel bleeding who were diagnosed with a Dieulafoy's lesion by capsule endoscopy or double-balloon enteroscopy. RESULTS AND CONCLUSIONS: all patients underwent combined endoscopic treatment. During a median follow-up of 33.5 months (range, 2-145), three of the 12 cases that stayed in follow-up (25 %) recurred, all within 48 hours after treatment. Two were successfully re-treated with a repeat endoscopic procedure.

Small bowel enteroscopy - A joint clinical guideline by the Spanish and Portuguese small-bowel study groups.

The present evidence-based guidelines are focused on the use of device-assisted enteroscopy in the management of small-bowel diseases. A panel of experts selected by the Spanish and Portuguese small-bowel study groups reviewed the available evidence focusing on the main indications of this technique, its role in the management algorithm of each indication, and its diagnostic and therapeutic yield. A set of recommendations was issued accordingly.