The effects of signal transducer and activator of transcription three mutations on human platelets

Involvement of signal transducer and activator of transcription 3 (STAT3) in inflammation is well known. Recently, a role for STAT3 in platelet activation and platelet production has been suggested. Platelets exhibit important immune functions and engagement of STAT3 in platelet physiology may link inflammation and hemostasis. This study investigated the effects of STAT3 loss-of-function mutations and single nucleotide polymorphisms (SNPs) in STAT3 on glycoprotein VI (GPVI)-mediated platelet activation and platelet numbers in humans. Two cohorts were studied. The first cohort concerned patients with STAT3 loss-of-function mutations. Platelet numbers were investigated in eight patients and GPVI-mediated platelet activation was functionally tested in four patients. Additional experiments were performed to investigate underlying mechanisms. The second cohort concerned 334 healthy volunteers and investigated the consequences of SNPs in STAT3 on GPVI-mediated platelet activation and platelet numbers. Platelet activation was lower in STAT3 loss-of-function patients at baseline and after stimulation of the GPVI receptor, reflected by decreased P-selectin expression. This was independent of gene transcription. Blockade of the adenosine di-phosphate (ADP) pathway resulted in a further decrease of P-selectin expression, particularly in STAT3 loss-of-function patients. In contrast, the SNPs in STAT3 did not influence GPVI-mediated platelet activation. Also, platelet numbers were not affected by STAT3 loss-of-function mutations, nor was there an association with the SNPs. In conclusion, STAT3 signaling does not seem to play a major role in thrombopoiesis. We confirm that STAT3 is involved in GPVI-mediated platelet activation in humans, independent of gene transcription. GPVI-mediated platelet activation is highly dependent on secondary ADP release. Our findings suggest that STAT3 modulation may affect inflammation, hemostasis, and their interaction.</p

Phage-derived protein induces increased platelet activation and is associated with mortality in patients with invasive pneumococcal disease

To improve our understanding about the severity of invasive pneumococcal disease (IPD), we investigated the association between the genotype of Streptococcus pneumoniae and disease outcomes for 349 bacteremic patients. A pneumococcal genome-wide association study (GWAS) demonstrated a strong correlation between 30-day mortality and the presence of the phage-derived gene pblB, encoding a platelet-binding protein whose effects on platelet activation were previously unknown. Platelets are increasingly recognized as key players of the innate immune system, and in sepsis, excessive platelet activation contributes to microvascular obstruction, tissue hypoperfusion, and finally multiorgan failure, leading to mortality. Our in vitro studies revealed that pblB expression was induced by fluoroquinolones but not by the beta-lactam antibiotic penicillin G. Subsequently, we determined pblB induction and platelet activation by incubating whole blood with the wild type or a pblB knockout mutant in the presence or absence of antibiotics commonly administered to our patient cohort. pblB-dependent enhancement of platelet activation, as measured by increased expression of the ɑ-granule protein P-selectin, the binding of fibrinogen to the activated ɑ IIbβ3 receptor, and the formation of platelet-monocyte complex occurred irrespective of antibiotic exposure. In conclusion, the presence of pblB on the pneumococcal chromosome potentially leads to increased mortality in patients with an invasive S. pneumoniae infection, which may be explained by enhanced platelet activation. This study highlights the clinical utility of a bacterial GWAS, followed by functional characterization, to identify bacterial factors involved in disease severity. IMPORTANCE The exact mechanisms causing mortality in invasive pneumococcal disease (IPD) patients are not completely understood. We examined 349 patients with IPD and found in a bacterial genome-wide association study (GWAS) that the presence of the phage-derived gene pblB was associated with mortality in the first 30 days after hospitalization. Although pblB has been extensively studied in Streptococcus mitis, its consequence for the interaction between platelets and Streptococcus pneumoniae is largely unknown. Platelets are important in immunity and inflammation, and excessive platelet activation contributes to microvascular obstruction and multiorgan failure, leading to mortality. We therefore developed this study to assess whether the expression of pblB might increase the risk of death for IPD patients through its effect on enhanced platelet activation. This study also shows the value of integrating extensive bacterial genomics and clinical data in predicting and understanding pathogen virulence, which in turn will help to improve prognosis and therapy

Black Fungus Complicated with COVID-19 in a Man with Underlying Non-Hodgkin’s Lymphoma

COVID-19 is a disease reported to suppress cellular immunity. This may lead to the development of opportunistic infections, among others black fungus, or mucormycosis. On the other hand, pre-existing defect in immunity may render patients susceptible to both mucormycosis and COVID-19. Mucormycosis is a relatively rare fungal infection with rapid progression unless diagnosed promptly and treated adequately, and urgent surgical and medical intervention is lifesaving. The manifestation of mucormycosis largely depends on the presence of exposure to the pathogen and the existing risk factor of the host. As black fungus is locally invasive, the majority of cases will involve tissue damage with local destruction and contiguous spread to nearby structure. We here with present a case of black fungus complicated with COVID-19 in a man with underlying non-Hodgkin’s lymphoma

Parenteral and Oral Anticoagulant Treatment for Hospitalized and Post-Discharge COVID-19 Patients: A Systematic Review and Meta-Analysis

Background: The use of anticoagulants has been endorsed by different hematological societies as coagulation abnormalities are key features of COVID-19 patients. This systematic review and meta-analysis aims to provide the most recent update on available evidence on the clinical benefits and risk of oral and parenteral anticoagulants, as well agents with anticoagulant properties, in hospitalized and post-discharge COVID-19 patients. Methods: This systematic review synthesizes data on the outcome of anticoagulation in hospitalized and post-discharge COVID-19 patients. Dichotomous variables from individual studies were pooled by risk ratio (RR) and their 95% confidence interval (95% CI) using the random-effects model. Meta-analyses were performed when feasible. Results: We included 32 studies from 2.815 unique citations, including 7 randomized clinical trials. A total of 33.494 patients were included. Outcomes measured include mortality and survival rates, the requirement for ICU care and mechanical ventilation. A pooled meta-analysis favors anticoagulant compared to no anticoagulant with reduced mortality in hospitalized patients (RR 0,55; 95%CI 0,43-0,66; p<0,001). Higher dose of anticoagulant also showed treatment benefit compared to standard prophylactic dose in selected populations (RR 0,68; 95%CI 0,40-0,96; p<0,001). Regular, pre-hospital anticoagulation prior to hospitalization yielded mixed result. There are currently no data on the benefit of anticoagulation on post-discharge COVID-19 patients. Conclusion: Determination of the presence of thrombosis in COVID-19 is important, as therapeutic dosage of anticoagulants, rather than prophylatic dose, would be indicated in such clinical situation. Anticoagulants were found to decrease the mortality of hospitalized COVID-19. The results from this study are important in the tailored treatment of COVID-19 patients. Further studies on the need for oral anticoagulation for outpatients or post-discharge is warranted. This study has been registered in PROSPERO database (CRD42020201418)

Extrapulmonary Manifestations COVID-19

After being declared as a pandemic on March 11, 2020 by the World Health Organization, COVID-19 has affected 497 million people worldwide as of 9 April 2022. COVID-19 is a disease with a plethora of clinical manifestations, which extends to those beyond pulmonary signs and symptoms. Studies that report on the clinical presentation of COVID-19 rarely report specifically on cases with only extrapulmonary manifestations of COVID-19. Extrapulmonary clinical presentations of COVID-19 without pulmonary signs and symptoms is rare, and in such cases, COVID-19 is rarely suspected.We herewith describe four patients with extrapulmonary manifestations of COVID-19, with positive SARS-COV-2 PCR when the test was performed for initial patient screening. The first patient is a 44-year-old female who developed painful ulcer with burning sensation at the lateral side of the tongue along with low grade fever. This symptom appeared after the initial complaints of coughing and nasal congestion subsided.  The second patient is a 37-year-old male, who complained of red eyes  with itchiness and increased tear production for 3 days before seeing an ophthalmologist. The third patient is a 44-year-old female who developed burning sensation and soreness on her throat upon swallowing with fever and chills. These symptoms appear consecutively without any respiratory complaint. The fourth patient is a previously healthy, 30-year-old female, with a normal weight and BMI, and without any comorbidity, cardiovascular risk and neither personal nor family history of cardiovascular disease. In these 4 patients, COVID-19 stomatitis, conjunctivitis, pharyngitis and COVID-19-associated atrial fibrillation was subsequently diagnosed, respectively.In the pandemic stage of COVID-19, COVID-19 screening has often been routinely performed due to the high risk of transmission. However, the decrease in the number of COVID-19 cases may prompt physicians to perform SARS-COV-2 testing based on clinical suspicion. It is imperative to consider the likelihood of COVID-19 and perform SARS-COV-2 PCR in patients with extrapulmonary complaints that have persisting complaints despite treatment

Higher platelet reactivity and platelet-monocyte complex formation in Gram-positive sepsis compared to Gram-negative sepsis

Platelets may play a role in the high risk for vascular complications in Gram-positive sepsis. We compared the platelet reactivity of 15 patients with Gram-positive sepsis, 17 with Gram-negative sepsis and 20 healthy controls using a whole blood flow cytometry-based assay. Patients with Gram-positive sepsis had the highest median fluorescence intensity (MFI) of the platelet membrane expression of P-selectin upon stimulation with high dose adenosine diphosphate (ADP; P = 0.002 vs. Gram-negative and P = 0.005 vs. control groups) and cross-linked collagen-related peptide (CRP-XL; P = 0.02 vs. Gram-negative and P = 0.0001 vs. control groups). The Gram-positive group also demonstrated significantly higher ADP-induced fibrinogen binding (P = 0.001), as wll as platelet-monocyte complex formation (P = 0.02), compared to the Gram-negative group and had the highest plasma levels of platelet factor 4, β-thromboglobulin and soluble P-selectin. In contrast, thrombin-antithrombin complex and C-reactive protein levels were comparable in both patient groups. In conclusion, common Gram-positive pathogens induce platelet hyperreactivity, which may contribute to a higher risk for vascular complications

The influence of hypoxia on platelet function and plasmatic coagulation during systemic inflammation in humans in vivo

Contains fulltext : 207956.pdf (publisher's version ) (Open Access

Molecular analyses in Indonesian individuals with intellectual disability and microcephaly

Background Intellectual disability (ID) often coincides with an abnormal head circumference (HC). Since the HC is a reflection of brain size, abnormalities in HC may be a sign of a brain anomaly. Although microcephaly is often secondary to ID, hereditary (autosomal recessive) forms of primary microcephaly (MCPH) exist that result in ID. Objective To investigate mutations in MCPH genes in patients with ID and microcephaly. Methods From a population of 527 Indonesian individuals with ID, 48 patients with microcephaly (9.1 %) were selected. These patients were previously found to be normal upon conventional karyotyping, fragile X mental retardation 1 (FMRl) gene analysis, subtelomeric deletion, and duplication multiplex ligationdependent probe amplification (MLPA). Sanger sequencing for abnormal spindle-like microcephaly-associated (ASPM) and WD repeat domain 62 (WDR62) was performed in all 48 subjects, while sequencing for microcephalin (MCPHl), cyclin-dependent kinase 5 (CDK5) regulatory subunit-associated protein 2 (CD5KRAP2) , centromere protein} (CENPJ), and SCUfALl interrupting locus (STIL) was conducted in only the subjects with an orbitofrontal cortex (OFC) below -4 SD. Results In all genes investigated, 66 single nucleotide polymorphisms (SNPs) and 15 unclassified variants which were predicted as unlikely to be pathogenic (lN2), were identified. Possible pathogenic variants (lN3) were identified in ASPM. However, since none of the patients harboured compound heterozygous likely pathogenic mutations, no molecular MCPH diagnosis could be established. Interestingly, one of the patients harboured the same variants as her unaffected monozygotic twin sister, indicating that our cohort included a discordant twin. Conclusions This study is the first to investigate for possible genetic causes ofMCPH in the Indonesian population. The absence of causative pathogenic mutations in the MCPH genes tested may originate from several factors. The identification of UV2 and UV3 variants as well as the absence of causative pathogenic mutations calls for further investigations