Insulin-degrading enzyme (IDE) as a modulator of microglial phenotypes in the context of Alzheimer's disease and brain aging.

The insulin-degrading enzyme (IDE) is an evolutionarily conserved zinc-dependent metallopeptidase highly expressed in the brain, where its specific functions remain poorly understood. Besides insulin, IDE is able to cleave many substrates in vitro, including amyloid beta peptides, making this enzyme a candidate pathophysiological link between Alzheimer's disease (AD) and type 2 diabetes (T2D). These antecedents led us to address the impact of IDE absence in hippocampus and olfactory bulb. A specific induction of microgliosis was found in the hippocampus of IDE knockout (IDE-KO) mice, without any effects in neither hippocampal volume nor astrogliosis. Performance on hippocampal-dependent memory tests is influenced by IDE gene dose in 12-month-old mice. Furthermore, a comprehensive characterization of the impact of IDE haploinsufficiency and total deletion in metabolic, behavioral, and molecular parameters in the olfactory bulb, a site of high insulin receptor levels, reveals an unambiguous barcode for IDE-KO mice at that age. Using wildtype and IDE-KO primary microglial cultures, we performed a functional analysis at the cellular level. IDE absence alters microglial responses to environmental signals, resulting in impaired modulation of phenotypic states, with only transitory effects on amyloid-ß management. Collectively, our results reveal previously unknown physiological functions for IDE in microglia that, due to cell-compartment topological reasons, cannot be explained by its enzymatic activity, but instead modulate their multidimensional response to various damaging conditions relevant to aging and AD conditions.

Molecular and Serological Studies on Potential SARS-CoV-2 Infection among 43 Lemurs under Human Care-Evidence for Past Infection in at Least One Individual.

In the setting of the recent COVID-19 pandemic, transmission of SARS-CoV-2 to animals has been reported in both domestic and wild animals and is a matter of concern. Given the genetic and functional similarities to humans, non-human primates merit particular attention. In the case of lemurs, generally considered endangered, they are believed to be susceptible to SARS-CoV-2 infection. We have conducted a study for evidence of SARS-CoV-2 infection among the 43 lemurs of Mundomar, a zoological park in Benidorm, Spain. They belong to two endangered lemur species, 23 black-and-white ruffed lemurs (Varecia variegata) and 20 ring-tailed lemurs (Lemur catta). Health assessments conducted in 2022 and 2023 included molecular analyses for SARS-CoV-2 RNA of oral and rectal swabs using two different RT-qPCR assays, always with negative results for SARS-CoV-2 in all animals. The assessment also included serological testing for antibodies against the receptor-binding domain (RBD) of the spike protein (S) of SARS-CoV-2, which again yielded negative results in all animals except one black-and-white ruffed lemur, supporting prior infection of that animal with SARS-CoV-2. Our data, while not indicating a high susceptibility of lemurs to SARS-CoV-2 infection, show that they can be infected, adding to the existing information body on potential ways for SARS-CoV-2 virus spreading in zoos, highlighting the need for animal surveillance for the virus.

The Cdc14 Phosphatase Controls Resolution of Recombination Intermediates and Crossover Formation during Meiosis.

Meiotic defects derived from incorrect DNA repair during gametogenesis can lead to mutations, aneuploidies and infertility. The coordinated resolution of meiotic recombination intermediates is required for crossover formation, ultimately necessary for the accurate completion of both rounds of chromosome segregation. Numerous master kinases orchestrate the correct assembly and activity of the repair machinery. Although much less is known, the reversal of phosphorylation events in meiosis must also be key to coordinate the timing and functionality of repair enzymes. Cdc14 is a crucial phosphatase required for the dephosphorylation of multiple CDK1 targets in many eukaryotes. Mutations that inactivate this phosphatase lead to meiotic failure, but until now it was unknown if Cdc14 plays a direct role in meiotic recombination. Here, we show that the elimination of Cdc14 leads to severe defects in the processing and resolution of recombination intermediates, causing a drastic depletion in crossovers when other repair pathways are compromised. We also show that Cdc14 is required for the correct activity and localization of the Holliday Junction resolvase Yen1/GEN1. We reveal that Cdc14 regulates Yen1 activity from meiosis I onwards, and this function is essential for crossover resolution in the absence of other repair pathways. We also demonstrate that Cdc14 and Yen1 are required to safeguard sister chromatid segregation during the second meiotic division, a late action that is independent of the earlier role in crossover formation. Thus, this work uncovers previously undescribed functions of the evolutionary conserved Cdc14 phosphatase in the regulation of meiotic recombination.

Comparison of COVID-19 and Non-COVID-19 Pneumonia in Down Syndrome.

Whether the increased risk for coronavirus disease 2019 (COVID-19) hospitalization and death observed in Down syndrome (DS) are disease specific or also occur in individuals with DS and non-COVID-19 pneumonias is unknown. This retrospective cohort study compared COVID-19 cases in persons with DS hospitalized in Spain reported to the Trisomy 21 Research Society COVID-19 survey (n = 86) with admissions for non-COVID-19 pneumonias from a retrospective clinical database of the Spanish Ministry of Health (n = 2832 patients). In-hospital mortality rates were significantly higher for COVID-19 patients (26.7% vs. 9.4%), especially among individuals over 40 and patients with obesity, dementia, and/or epilepsy. The mean length of stay of deceased patients with COVID-19 was significantly shorter than in those with non-COVID-19 pneumonias. The rate of admission to an ICU in patients with DS and COVID-19 (4.3%) was significantly lower than that reported for the general population with COVID-19. Our findings confirm that acute SARS-CoV-2 infection leads to higher mortality than non-COVID-19 pneumonias in individuals with DS, especially among adults over 40 and those with specific comorbidities. However, differences in access to respiratory support might also account for some of the heightened mortality of individuals with DS with COVID-19.

Treatment with proton pump inhibitors as a cofactor in adverse reactions of patients undergoing oral food immunotherapy.

BACKGROUND AND OBJECTIVES: Based on previous studies revealing acid-suppression medication as a risk factor for food allergy tolerance induction, we aimed to establish the importance of those findings in patients undergoing oral immunotherapy (OIT). MATERIALS AND METHODS, RESULTS: We describe a case series of four patients who underwent milk OIT with a concomitant use of proton pump inhibitor (PPI) medication and who developed anaphylaxis after a known, previously tolerated dose of milk. CONCLUSIONS: PPIs may act as a cofactor in patients undergoing OIT, triggering adverse reactions, irrespective of the PPI used or the dosage. It would be necessary to separate the administration of drug from food intake.Since OIT is a new form of treatment, long-term adverse events arising from PPI treatment and other possible triggers are still uncertain. Consequently, monitoring of patient must be prolonged over time. Additional investigations on the influence of different drugs in OIT maintenance phase are required.

Treatment with proton pump inhibitors as a cofactor in adverse reactions of patients undergoing oral food immunotherapy

Background and objectives Based on previous studies revealing acid-suppression medication as a risk factor for food allergy tolerance induction, we aimed to establish the importance of those findings in patients undergoing oral immunotherapy (OIT). Materials and methods, results We describe a case series of four patients who underwent milk OIT with a concomitant use of proton pump inhibitor (PPI) medication and who developed anaphylaxis after a known, previously tolerated dose of milk. Conclusions PPIs may act as a cofactor in patients undergoing OIT, triggering adverse reactions, irrespective of the PPI used or the dosage. It would be necessary to separate the administration of drug from food intake. Since OIT is a new form of treatment, long-term adverse events arising from PPI treatment and other possible triggers are still uncertain. Consequently, monitoring of patient must be prolonged over time. Additional investigations on the influence of different drugs in OIT maintenance phase are required (AU)

Protein degradation in a LAMP-2-deficient B-lymphoblastoid cell line from a patient with Danon disease.

Danon disease, a condition characterized by cardiomyopathy, myopathy, and intellectual disability, is caused by mutations in the LAMP-2 gene. Lamp-2A protein, generated by alternative splicing from the Lamp-2 pre-mRNA, is reported to be the lysosomal membrane receptor essential for the chaperone-mediated autophagic pathway (CMA) aimed to selective protein targeting and translocation into the lysosomal lumen for degradation. To study the relevance of Lamp-2 in protein degradation, a lymphoblastoid cell line was obtained by EBV transformation of B-cells from a Danon patient. The derived cell line showed no significant expression of Lamp-2 protein. The steady-state mRNA and protein levels of alpha-synuclein, IΚBα, Rcan1, and glyceraldehyde-3-phosphate dehydrogenase, four proteins reported to be selective substrates of the CMA pathway, were similar in control and Lamp-2-deficient cells. Inhibition of protein synthesis showed that the half-life of alpha-synuclein, IΚBα, and Rcan1 was similar in control and Lamp-2-deficient cells, and its degradation prevented by proteasome inhibitors. Both in control and Lamp-2-deficient cells, induction of CMA and macroautophagy by serum and aminoacid starvation of cells for 8h produced a similar decrease in IΚBα and Rcan1 protein levels and was prevented by the addition of lysosome and autophagy inhibitors. In conclusion, the results presented here showed that Lamp-2 deficiency in human lymphoblastoid cells did not modify the steady-state levels or the degradation of several protein substrates reported as selective substrates of the CMA pathway.

Safety and anti-HCV effect of prolonged intravenous silibinin in HCV genotype 1 subjects in the immediate liver transplant period.

BACKGROUND & AIMS: Reinfection of the graft is the rule in patients with HCV cirrhosis undergoing liver transplantation, and HCV-RNA reaches pre-transplantation levels within the first month. Short-term intravenous silibinin monotherapy is safe and shows a potent in vivo anti-HCV effect. We aimed at evaluating the safety and antiviral effect of prolonged intravenous silibinin, started immediately before liver transplantation. METHODS: Single centre, prospective, pilot study, to assess the safety and effect on HCV-RNA kinetics during at least 21 days of intravenous silibinin monotherapy (20 mg/kg/day) in 9 consecutive HCV genotype 1 subjects, in comparison to a control, non-treated group of 7 consecutive prior transplanted subjects under the same immunosuppressive regimen (basiliximab, steroids, delayed tacrolimus, micophenolate). RESULTS: Intravenous silibinin led to significant, maintained and progressive HCV-RNA decreases (mean HCV-RNA drop at week 3, -4.1 ± 1.3 log(10)IU/ml), and lack of viral breakthrough during administration. Four patients (44%) reached negative HCV-RNA, maintained during silibinin treatment, vs. none in the control group, but HCV-RNA relapsed in all of them after a median of 21 days (16-28), following silibinin withdrawal. Partial responders to silibinin showed marked decreases in HCV-RNA when compared to controls, but lower than complete responders. There were no clinical adverse effects, and silibinin led to asymptomatic transient hyperbilirubinemia (week 2, 4.2 ± 2.2 vs. 2.5 ± 3.6 mg/dl; p=0.02). CONCLUSIONS: Prolonged intravenous silibinin monotherapy was safe in the immediate liver transplantation period, leading to a potent and time dependent antiviral effect and lack of HCV-RNA breakthrough during administration. However, HCV-RNA rebounded after withdrawal, and silibinin monotherapy did not avoid reinfection of the graft.

Cross Hypersensitivity Syndrome between Phenytoin and Carbamazepine.

OBJECTIVE: To evaluate the incidence of cross anticonvulsant hypersensitivity syndrome (AHS) between phenytoin (PHT) and carbamazepine (CBZ) in hospitalized patients. METHOD: Retrospective chart review about the cross AHS was retrieved from pharmacy adverse drug reaction program from 1998 to 2002 in a 450-bed teaching hospital. MAIN OUTCOME MEASURES: AHS was defined as the appearance of at least two symptoms with the first anticonvulsant drug (ACD). Cross AHS was considered if after withdrawal of a first ACD because of hypersensitivity symptoms, a new episode with similar or new symptoms appeared after exposure to a second ACD. The following symptoms were considered- rash, fever, hepatotoxicity, lymphadenopathies or hematological disturbances. RESULTS: Cross AHS between PHT and CBZ was observed in nine cases (45). After the cross-reaction event, four of them were treated with valproic acid, two with vigabatrin, two with phenobarbital and one with no treatment without developing further AHS. CONCLUSIONS: AHS is a severe complication of aromatic ACD that can compromise the future choice of therapy. Because of the high incidence of clinical cross-reaction between these two drugs, non-aromatic ACD alternatives, must be considered.