Publications by authors named "Rafael Manez"

Article Synopsis
  • Aortic valve calcification (AVC) was studied in patients with bioprosthetic valves to assess its impact on patient prognosis.
  • In a study of 361 patients who had valve replacements, AVC was found to be significantly higher in those with structural valve degeneration (SVD).
  • The results indicate that AVC greater than 100 Agatston units is correlated with worse health outcomes and increased risk of mortality and cardiovascular events, making CT scans a valuable tool for evaluation.
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Information on the long-term effects of non-restrictive antimicrobial stewardship (AMS) strategies is scarce. We assessed the effect of a stepwise, multimodal, non-restrictive AMS programme on broad-spectrum antibiotic use in the intensive care unit (ICU) over an 8-year period. Components of the AMS were progressively implemented.

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  • Researchers studied how removing certain antibodies can enhance protection against Gram-negative bacterial infections, focusing on anti-αGal antibodies.
  • In experiments with genetically modified mice lacking these antibodies, they found improved survival rates from bacterial sepsis and better bacterial killing capability in their serum.
  • The study suggests that inhibiting anti-αGal antibodies in both mice and human serum can boost the immune response against dangerous bacteria, pointing to new ways to prevent infections.
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Structural valve deterioration (SVD) of bioprosthetic heart valves (BHVs) has great clinical and economic consequences. Notably, immunity against BHVs plays a major role in SVD, especially when implanted in young and middle-aged patients. However, the complex pathogenesis of SVD remains to be fully characterized, and analyses of commercial BHVs in standardized-preclinical settings are needed for further advancement.

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Carbohydrate-specific antibodies are significant mediators of xenograft rejection. This study analyzed the carbohydrate specificity of antibodies in baboons before and after xenotransplantation of organs or injection of porcine red blood cells from hDAF transgenic pigs, using a glycan array with structurally defined glycans. Antibodies against hyaluronic acid disaccharide (HA2) showed the highest reactivity at baseline and rose after xenogeneic exposure.

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The cause of structural valve deterioration (SVD) is unclear. Therefore, we investigated oxidative stress markers in sera from patients with bioprosthetic heart valves (BHVs) and their association with SVD. Blood samples were taken from SVD (Phase A) and BHV patients during the first 24 (Phase B1) and >48 months (Phase B2) after BHV implantation to assess total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrotyrosine (NT).

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  • Anti-αGal IgE antibodies are responsible for αGal-syndrome (AGS), an allergic condition that develops in individuals after hard tick bites, leading to increased sensitivity to αGal.
  • The study explores the creation of polymeric αGal-glycoconjugates aimed at inhibiting these IgE antibodies, with promising results in both human serum samples and a mouse model.
  • The findings indicate that a minimum of 27 αGal residues is required for effective inhibition, and the specific polymeric conjugate DP1000-RA0118 demonstrated significant reduction of anti-αGal IgE antibodies, supporting its potential for clinical application in treating AGS.
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Bioprosthetic heart valves (BHVs) are commonly used to replace severely diseased heart valves but their susceptibility to structural valve degeneration (SVD) limits their use in young patients. We hypothesized that antibodies against immunogenic glycans present on BHVs, particularly antibodies against the xenoantigens galactose-α1,3-galactose (αGal) and N-glycolylneuraminic acid (Neu5Gc), could mediate their deterioration through calcification. We established a large longitudinal prospective international cohort of patients (n = 1668, 34 ± 43 months of follow-up (0.

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Background: Non-invasive oxygenation strategies have a prominent role in the treatment of acute hypoxemic respiratory failure during the coronavirus disease 2019 (COVID-19). While the efficacy of these therapies has been studied in hospitalized patients with COVID-19, the clinical outcomes associated with oxygen masks, high-flow oxygen therapy by nasal cannula and non-invasive mechanical ventilation in critically ill intensive care unit (ICU) patients remain unclear.

Methods: In this retrospective study, we used the best of nine covariate balancing algorithms on all baseline covariates in critically ill COVID-19 patients supported with > 10 L of supplemental oxygen at one of the 26 participating ICUs in Catalonia, Spain, between March 14 and April 15, 2020.

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Background: The α1,3-galactosyltransferase gene-knockout (GalT KO) mice are able to produce natural anti-αGal antibodies apparently without any specific immunization. GalT KO mice are commonly used as a model immunological system for studying anti-αGal responses to Gal-positive xenografts in human. In this study, we compared the specificity of mouse and human αGal antibodies to realize the adequacy of the murine model.

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Humans cannot synthesize N-glycolylneuraminic acid (Neu5Gc) but dietary Neu5Gc can be absorbed and deposited on endothelial cells (ECs) and diet-induced anti-Neu5Gc antibodies (Abs) develop early in human life. While the interaction of Neu5Gc and diet-induced anti-Neu5Gc Abs occurs in all normal individuals, endothelium activation by elicited anti-Neu5Gc Abs following a challenge with animal-derived materials, such as following xenotransplantation, had been postulated. Ten primary human EC preparations were cultured with affinity-purified anti-Neu5Gc Abs from human sera obtained before or after exposure to Neu5Gc-glycosylated rabbit IgGs (elicited Abs).

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Article Synopsis
  • Gut commensal bacteria play a crucial role in maintaining immune balance, and changes in their composition are linked to diseases like autoimmunity and inflammation.
  • Researchers studied the gut microbiota of GalT-KO mice over 7 months using advanced sequencing methods, focusing on the diversity of specific bacterial types and their correlation with natural anti-glycan antibodies.
  • Findings suggest that specific bacterial orders are linked to the development of these antibodies, with changes in microbiota diversity impacting antibody levels and types, although not all diversity changes affect the gut microbiome's overall function.
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The repertoire of circulating anti-carbohydrate antibodies of a given individual is often associated with its immunological status. Not only the individual immune condition determines the success in combating internal and external potential threat signals, but also the existence of a particular pattern of circulating anti-glycan antibodies (and their serological level variation) could be a significant marker of the onset and progression of certain pathological conditions. Here, we describe a Printed Glycan Array (PGA)-based methodology that offers the opportunity to measure hundreds of glycan targets with very high sensitivity; using a minimal amount of sample, which is a common restriction present when small animals (rats, mice, hamster, etc.

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  • Xenogeneic chondrocytes (porcine articular chondrocytes) could be a promising option for repairing cartilage in joints, but their introduction into a host body triggers an immune response.
  • In a study involving Lewis rats, the route of mesenchymal stem cells (MSCs) administration significantly affected their survival and biodistribution, with intravenous (i.v.) injections leading to rapid decline whereas intraperitoneal (i.p.) injections lasted longer locally.
  • Despite some MSC administration methods, there was no reduction in the immune response against xenogeneic chondrocytes; in fact, injecting MSCs prior to chondrocytes actually enhanced the antibody response against the xenogeneic cells.
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One of the most common genetic backgrounds for mice used as a model to investigate human diseases is the inbred BALB/c strain. This work is aimed to characterize the pattern of natural anti-carbohydrate antibodies present in the serum of 20 BALB/c mice by printed glycan array technology and to compare their binding specificities with that of human natural anti-carbohydrate antibodies. Natural antibodies (NAbs) from the serum of BALB/c mice interacted with 71 glycans from a library of 419 different carbohydrate structures.

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Selective depletion of natural anti-Galα1-3Galβ1-4GlcNAc (so-called anti-αGal) antibodies is achieved in α1,3-galactosyltransferase knockout (Gal-KO) mice by administration of the soluble glycoconjugate of αGal GAS914. This molecule removed up to 90% of natural circulating anti-αGal antibodies without causing unspecific production of cytokines in wild-type (CBA) and Gal-KO mice. However, the removal of anti-αGal antibodies in Gal-KO mice with GAS914 in the context of sepsis after cecal ligation and puncture (CLP) was associated with a significant increase in the production of leptin, CXLC1, CXLC13, and TIMP-1 cytokines compared to vehicle (PBS)-treated controls.

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Background: Currently, no vaccine against Pseudomonas is available. IC43 is a new, recombinant, protein (OprF/I)-based vaccine against the opportunistic pathogen, Pseudomonas aeruginosa, a major cause of serious hospital-acquired infections. IC43 has proven immunogenicity and tolerability in healthy volunteers, patients with burns, and patients with chronic lung diseases.

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Article Synopsis
  • Research highlights that humans cannot synthesize the sialic acid Neu5Gc, which is found in animal-derived cardiac tissues and bioprosthetic heart valves (BHV), making it a potential target for immune response.
  • Studies showed Neu5Gc expression in porcine and bovine cardiac tissues and BHV, with higher levels of Neu5Gc in pericardium compared to valve tissues.
  • Human antibodies specifically recognize Neu5Gc in BHV, suggesting that this immune response may contribute to the deterioration of bioprosthetic heart valves over time.
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Invasive pulmonary aspergillosis (IPA) is a rare pathology with increasing incidence mainly in critical care settings and recently in immunocompetent patients. The mortality of the disease is very high, regardless of an early diagnosis and aggressive treatment. Here, we report a case of a 56 yr old previously healthy woman who was found unconscious at home and admitted to the emergency room with mild respiratory insufficiency.

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Patients suffering from liver cirrhosis (LC) frequently require non-hepatic abdominal surgery, even before liver transplantation. LC is an important risk factor itself for surgery, due to the higher than average associated morbidity and mortality. This high surgical risk occurs because of the pathophysiology of liver disease itself and to the presence of contributing factors, such as coagulopathy, poor nutritional status, adaptive immune dysfunction, cirrhotic cardiomyopathy, and renal and pulmonary dysfunction, which all lead to poor outcomes.

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Objectives: Although hyperlactatemia is common after cardiac surgery, its value as a prognostic marker is unclear. The aim of the present study was to determine whether postoperative serial arterial lactate (AL) measurements after cardiac surgery could predict outcome.

Design: Prospective, observational study.

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Article Synopsis
  • The study explored the effects of immunizing Lewis rats with hamster blood, which boosted xenoantibodies, and found this led to decreased survival rates after inducing low-grade sepsis through cecal ligation and puncture (CLP) (45% vs. 90% survival, p<0.01).
  • Contrary to expectations, there was no bacterial load in the blood of the rats after CLP, suggesting that the increased mortality was not due to a direct effect of the xenoantibodies on bacteria.
  • The study concluded that the inflammatory response, particularly the increase in certain cytokines, was more significant in determining survival outcomes, with non-infectious systemic inflammation playing a critical role in the observed reduced survival post
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Liver cirrhosis has evolved an important risk factor for cardiac surgery due to the higher morbidity and mortality that these patients may suffer compared with general cardiac surgery population. The presence of contributing factors for a poor outcome, such as coagulopathy, a poor nutritional status, an adaptive immune dysfunction, a degree of cirrhotic cardiomyopathy, and a degree of renal and pulmonary dysfunction, have to be taken into account for surgical evaluation when cardiac surgery is needed, together with the degree of liver disease and its primary complications. The associated pathophysiological characteristics that liver cirrhosis represents have a great influence in the development of complications during cardiac surgery and the postoperative course.

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Purpose: Obesity influences risk stratification in cardiac surgery in everyday practice. However, some studies have reported better outcomes in patients with a high body mass index (BMI): this is known as the obesity paradox. The aim of this study was to quantify the effect of diverse degrees of high BMI on clinical outcomes after cardiac surgery, and to assess the existence of an obesity paradox in our patients.

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  • Early tracheotomy performed before day eight of mechanical ventilation may lead to shorter sedation times compared to late tracheotomy, based on a randomized controlled trial.
  • The study included 489 ICU patients, with 245 in the early tracheotomy group and 244 in the late group, showing significant differences in sedation duration but similar mortality rates at 90 days.
  • Although the early procedure resulted in more ventilator-free days and decreased ICU length of stay in the subset of patients accepted for tracheotomy, the study was not sufficiently powered to conclusively prove additional benefits.
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