Cell division requires the regulation of karyokinesis and cytokinesis, which includes an essential role of the achromatic spindle. Although the functions of centrosomes are well characterised in somatic cells, their role during vertebrate spermatogenesis remains elusive. We have studied the dynamics of the meiotic centrosomes in male mouse during both meiotic divisions. Results show that meiotic centrosomes duplicate twice: first duplication occurs in the leptotene/zygotene transition, while the second occurs in interkinesis. The maturation of duplicated centrosomes during the early stages of prophase I and II are followed by their separation and migration to opposite poles to form bipolar spindles I and II. The study of the genetic mouse model Plk1(Δ/Δ) indicates a central role of Polo‐like kinase 1 in pericentriolar matrix assembly, in centrosome maturation and migration, and in the formation of the bipolar spindles during spermatogenesis. In addition, in vitro inhibition of Polo‐like kinase 1 and Aurora A in organotypic cultures of seminiferous tubules points out to a prominent role of both kinases in the regulation of the formation of meiotic bipolar spindles.

Summary Background Patients with gastrointestinal bleeding during anticoagulant and/or antiplatelet therapy represent a clinical challenge. Aim To determine the risk/rates of rebleeding, vascular events and death in patients treated with antiplatelet or anticoagulant agents who developed major gastrointestinal bleeding Methods This was an observational cohort study of patients who developed gastrointestinal bleeding while on antiplatelet and/or anticoagulant therapy. Drug use information was collected prospectively during bleeding events. Cox proportional hazards models were used to evaluate rebleeding, vascular events and death. Results Among 871 patients (mean age 78.9 ± 8.6 years), 38.9% used an anticoagulant, 52.5% used an antiplatelet and 8.6% used both; 93.1% interrupted treatment after gastrointestinal bleeding and 80.5% restarted therapy within 7.6 ± 36.4 days; 38.7% had upper gastrointestinal bleeds, 46.7% lower gastrointestinal bleeds and 14.6% gastrointestinal bleeds of unknown origin. Median follow‐up was 24.9 months (IQR: 7.0‐38.0). Resumption of both therapies was associated with a higher risk of rebleeding, lower risk of ischaemic events or death and a similar risk for upper and lower gastrointestinal events. Resumption of therapy ≤ 7 days after bleeding showed a similar pattern with no differences in death. Rebleeding rates were higher in anticoagulant vs antiplatelet patients (138.0 vs 99.0 events per 1000 patient‐years), and the bleeding location was identical in 61.8% of cases. Conclusions Resumption of anticoagulant or antiplatelet therapy after a gastrointestinal bleeding event was associated with a lower risk of vascular events and death and a higher rebleeding risk. The benefits of early reinstitution of anticoagulant/antiplatelet therapy outweigh the gastrointestinal‐related risks.

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CD39/NTPDase1 has emerged as an important molecule that contributes to maintain inflammatory and coagulatory homeostasis. Various studies have hypothesized the possible role of CD39 in COVID-19 pathophysiology since no confirmatory data shed light in this regard. Therefore, we aimed to quantify CD39 expression on COVID-19 patients exploring its association with severity clinical parameters and ICU admission, while unraveling the role of purinergic signaling on thromboinflammation in COVID-19 patients. We selected a prospective cohort of patients hospitalized due to severe COVID-19 pneumonia (n=75), a historical cohort of Influenza A pneumonia patients (n=18) and sex/age-matched healthy controls (n=30). CD39 was overexpressed in COVID-19 patients’ plasma and immune cell subsets and related to hypoxemia. Plasma soluble form of CD39 (sCD39) was related to length of hospital stay and independently associated with intensive care unit admission (adjusted odds ratio 1.04, 95%CI 1.0-1.08, p=0.038), with a net reclassification index of 0.229 (0.118-0.287; p=0.036). COVID-19 patients showed extracellular accumulation of adenosine nucleotides (ATP and ADP), resulting in systemic inflammation and pro-coagulant state, as a consequence of purinergic pathway dysregulation. Interestingly, we found that COVID-19 plasma caused platelet activation, which was successfully blocked by the P2Y12 receptor inhibitor, ticagrelor. Therefore, sCD39 is suggested as a promising biomarker for COVID-19 severity. As a conclusion, our study indicates that CD39 overexpression in COVID-19 patients could be indicating purinergic signaling dysregulation, which might be at the basis of COVID-19 thromboinflammation disorder.

COVID-19 has emerged as a devastating disease in the last 2 years. Many authors appointed to the importance of kallikrein-kinin system (KKS) in COVID-19 pathophysiology as it is involved in inflammation, vascular homeostasis, and coagulation. We aim to study the bradykinin cascade and its involvement in severity of patients with COVID-19. This is an observational cohort study involving 63 consecutive patients with severe COVID-19 pneumonia and 27 healthy subjects as control group. Clinical laboratory findings and plasma protein concentration of KKS peptides [bradykinin (BK), BK1-8], KKS proteins [high–molecular weight kininogen (HK)], and KKS enzymes [carboxypeptidase N subunit 1 (CPN1), kallikrein B1 (KLKB1), angiotensin converting enzyme 2 (ACE2), and C1 esterase inhibitor (C1INH)] were analyzed. We detected dysregulated KKS in patients with COVID-19, characterized by an accumulation of BK1-8 in combination with decreased levels of BK. Accumulated BK1-8 was related to severity of patients with COVID-19. A multivariate logistic regression model retained BK1-8, BK, and D-dimer as independent predictor factors to intensive care unit (ICU) admission. A Youden’s optimal cutoff value of −0.352 was found for the multivariate model score with an accuracy of 92.9%. Multivariate model score-high group presented an odds ratio for ICU admission of 260.0. BK1-8 was related to inflammation, coagulation, and lymphopenia. Our data suggest that BK1-8/BK plasma concentration in combination with D-dimer levels might be retained as independent predictors for ICU admission in patients with COVID-19. Moreover, we reported KKS dysregulation in patients with COVID-19, which was related to disease severity by means of inflammation, hypercoagulation, and lymphopenia.

Background Management of Helicobacter pylori infection has been expanded from the gastroenterology specialist (GS) to primary care physicians (PCPs), with a large increase in requests for urea breath tests (UBT). Due to the lack of evidence at this level, we evaluated the appropriateness of UBT indications and treatment for H pylori infections between PCPs and GSs and the effect of introducing specific counseling to PCPs. Materials and Methods This was a quasi‐experimental study. Phase I included 650 consecutive UBT requested by PCPs (400) and GSs (250). Indications and treatments were classified as appropriate or inappropriate based on national guidelines. Data on eradication rates were also collected. In phase II, 240 UBT and patients' treatment outcomes were analyzed after individually counseling PCPs on both aspects. Results Of 1049 UBT, inappropriate indications in phase I were significantly higher in tests requested by PCP compared with GS (35.9% vs 7.2%; P < 0.001). Inappropriate treatment regimens were significantly higher for PCPs in phase I (65.8% vs 26.4%; P < 0.001). Consequently, eradication rates were significantly lower in patients treated by PCPs compared with those treated by GS (63.7% vs 81.4%; P = 0.004). A significant increase in adherence to appropriate treatment regimens (75.8% vs 34.2%; P < 0.001) and eradication rates (79.2% vs 63.7%; P = 0.002) were observed in the PCP group after counseling; however, the appropriateness of indications did not improve. Conclusions Patients infected with H pylori managed at the primary care level had poorer outcomes. The introduction of specific counseling for PCPs significantly improved treatment management, but not indications.

Severe COVID-19 disease leads to hypoxemia, inflammation and lymphopenia. Viral infection induces cellular stress and causes the activation of the innate immune response. The ubiquitin-proteasome system (UPS) is highly implicated in viral immune response regulation. The main function of the proteasome is protein degradation in its active form, which recognises and binds to ubiquitylated proteins. Some proteasome subunits have been reported to be upregulated under hypoxic and hyperinflammatory conditions. Here, we conducted a prospective cohort study of COVID-19 patients (n = 44) and age-and sex-matched controls (n = 20). In this study, we suggested that hypoxia could induce the overexpression of certain genes encoding for subunits from the α and β core of the 20S proteasome and from regulatory particles (19S and 11S) in COVID-19 patients. Furthermore, the gene expression of proteasome subunits was associated with lymphocyte count reduction and positively correlated with inflammatory molecular and clinical markers. Given the importance of the proteasome in maintaining cellular homeostasis, including the regulation of the apoptotic and pyroptotic pathways, these results provide a potential link between COVID-19 complications and proteasome gene expression.

Atherosclerosis is a common comorbidity of obstructive sleep apnea (OSA) patients, caused by the interaction of dyslipidemia and systemic inflammation. The OSA proinflammatory response is mediated by NLRP3 inflammasome activation, which requires a priming signal mediated by intermittent hypoxia and an activation signal provided by soluble stimulus present in plasma. Our objectives were to study the oxidized low-density lipoprotein (oxLDL) expression in OSA patients with or without early subclinical atherosclerosis (eSA) as well as its contribution to NLRP3 activation and tissue factor (TF) release.We analyzed oxLDL, key components of the NLRP3 inflammasome cascade, and TF in plasma and monocytes from OSA patients and non-apneic subjects, with or without eSA as determined by increased carotid intima-media thickness without the appearance of atherosclerotic plaques. The oxLDL contribution to NLRP3 inflammasome activation was assessed usingin vitromodels.High levels of ox-LDL were identified in plasma from OSA patients, particularly in those with eSA, as well as an overexpression of NLRP3 cascade components and TF. Furthermore,in vitromodels showed that both oxLDL and plasma from OSA patients with eSA act synergistically with intermittent hypoxia as a priming and activation signal of NLRP3 that enhances the inflammatory response, pyroptosis and TF release.In conclusion, OSA patients with eSA exhibit NLRP3 activation by intermittent hypoxia and the presence of ox-LDL capable of releasing TF, constituting a pathway for the interaction between dyslipidemia and systemic inflammation in the development of atherosclerotic lesions.