In patients infected by SARS‐CoV‐2 who experience an exaggerated inflammation leading to pneumonia, monocytes likely play a major role but have received poor attention. Thus, we analyzed peripheral ...blood monocytes from patients with COVID‐19 pneumonia and found that these cells show signs of altered bioenergetics and mitochondrial dysfunction, had a reduced basal and maximal respiration, reduced spare respiratory capacity, and decreased proton leak. Basal extracellular acidification rate was also diminished, suggesting reduced capability to perform aerobic glycolysis. Although COVID‐19 monocytes had a reduced ability to perform oxidative burst, they were still capable of producing TNF and IFN‐γ in vitro. A significantly high amount of monocytes had depolarized mitochondria and abnormal mitochondrial ultrastructure. A redistribution of monocyte subsets, with a significant expansion of intermediate/pro‐inflammatory cells, and high amounts of immature monocytes were found, along with a concomitant compression of classical monocytes, and an increased expression of inhibitory checkpoints like PD‐1/PD‐L1. High plasma levels of several inflammatory cytokines and chemokines, including GM‐CSF, IL‐18, CCL2, CXCL10, and osteopontin, finally confirm the importance of monocytes in COVID‐19 immunopathogenesis.
SYNOPSIS
Investigation of patients with COVID‐19 pneumonia revealed that SARS‐CoV‐2 infection affects innate immunity by reshaping peripheral blood monocyte subsets and altering their functionality, in terms of bioenergetics, membrane potential and expression of checkpoint inhibitors.
A peripheral blood increase in intermediate monocytes, reduction of classical monocytes, increase of circulating immature monocytes and upregulation of PD‐1 and PD‐L1 on such cells characterize patients with COVID‐19 pneumonia.
Monocytes display reduced oxidative phosphorylation, reduced extracellular acidification rate and altered mitochondrial ultrastructure.
Monocytes had a reduced capability to perform the respiratory burst, although they still remain able to produce inflammatory cytokines.
Several inflammatory cytokines and chemokine, including GM‐CSF, IL‐18, CCL2, IL‐6, CXCL10 and osteopontin are present at high concentration in plasma from COVID‐19 patients.
Investigation of patients with COVID‐19 pneumonia revealed that SARS‐CoV‐2 infection affects innate immunity by reshaping peripheral blood monocyte subsets and altering their functionality, in terms of bioenergetics, membrane potential and expression of checkpoint inhibitors.
COVID-19: room for treating T cell exhaustion? Riva, Giovanni; Nasillo, Vincenzo; Tagliafico, Enrico ...
Critical care (London, England),
05/2020, Letnik:
24, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In critically ill COVID-19 patients, indeed, massive cytokine storms (including IL-6, TNF-α, and other inflammatory biomarkers), as well as increments of circulating neutrophils and monocyte ...activation, are typically observed together with low T lymphocyte counts and functional exhaustion of effector T cell responses 1, 3, 4. ...ineffective and detrimental expansions of innate/humoral responses, alongside T cell suppression, are reminiscent of classical features of sepsis, which is currently defined as a life-threatening organ dysfunction induced by dysregulated host response to infection, being characterized not only by systemic hyperinflammation (SIRS) with related endothelial and organ damage, but also by impairment of adaptive T cell immunity. ...the relevant coagulation disorders observed in end-stage COVID-19 could also well fit with the idea that severe COVID-19 possibly represents a peculiar clinicopathologic manifestation of viral sepsis. Importantly, immune checkpoint inhibitors (ICIs), such as anti-PD-1 and anti-PD-L1 monoclonal antibodies, originally developed to improve antineoplastic T cell immunity, are undergoing clinical investigation in septic patients 5. ...it should be conceivable that, also in COVID-19 patients, ICIs may be tested to restore immune competence of exhausted T cell subsets and, in this context, to specifically improve the pivotal process of virus elimination, likely blunted in severe COVID-19.
COVID-19: more than a cytokine storm Riva, Giovanni; Nasillo, Vincenzo; Tagliafico, Enrico ...
Critical care (London, England),
09/2020, Letnik:
24, Številka:
1
Journal Article
Recenzirano
Odprti dostop
...in those COVID-19 patients showing massive hyperinflammation, a clinical diagnosis of sHLH/MAS may be appropriate and deserves further investigation at the histological level. ...severe COVID-19 ...has appeared as a peculiar clinicopathologic entity—yet poorly understood from a mechanistic viewpoint—which however, by definition, may represent a novel form of viral sepsis, being characterized by (a) T cell deficiencies, with early and progressive lymphopenia; (b) systemic hyperinflammation, with a peculiar time-course, often increasing at a late phase, when coagulopathy and fatal organ damage may eventually occur; and (c) COVID-19-associated coagulopathy, displaying some unique clinical and laboratory findings, compared with either disseminated intravascular coagulation or sepsis-induced coagulopathy 10. ...to maximize potential benefits of different immunotherapeutic approaches against COVID-19, adequate patients’ selection is warranted, possibly performed on the basis of putative biomarkers and immune profiles predictive of response. ...by considering the typical disease course, often prolonged for several weeks, the optimal timing for these treatments should be defined. ...it seems conceivable that, during SARS-CoV-2 infection, especially in elderly patients and less frequently in young people, something can go wrong at the delicate interface between effective viral clearance and T cell tolerance.
Dentin erosion is a frequent clinical condition that requires restorative interventions, especially in cases with moderate to severe wear. This requires clinicians to have knowledge about the ...characteristics of dentin, etiological factors involved, and restorative approaches to be made. Minimally invasive restorations have been indicated for rehabilitation of these cases, in order to preserve the largest possible amount of dental tissue. To achieve this, effective and durable adhesion to the eroded dentin must be obtained. However, the histological and morphological changes resulting from the erosive challenge have make eroded dentin a much more challenging substrate to treat than sound dentin. In order to minimize these limitations, mechanical and chemical strategies, as well as changes in the adhesive protocol, have been reported in the literature. The purpose of this review was to present these limitations and discuss the effectiveness of the strategies suggested, based on the results of bond strength to eroded dentin.
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Neurodegenerative diseases, as Parkinson’s disease (PD), involve irreversible neural cell damage and impairment. In PD, there is a selective degeneration of the dopaminergic neurons ...leading to motor symptoms. A common finding in PD neurodegeneration is the increase of reactive oxygen species (ROS), leading to oxidative stress. To date there are only interventions to relieve PD symptoms, however progress has been made in the development of therapies that target the immune system or use its components as therapeutic agents; among these, mesenchymal stem cells (MSCs), which are able to express neuroprotective factors as cytokines, chemokines and angiogenic molecules, collectively named secretome, that accumulate in MSC culture medium. However, lasting cell-free administration of secretome in vitro or in vivo is challenging. We used the conditioned media from rat adipose tissue-derived MSCs (RAA-MSCs) to check for neuroprotective activity towards pro-oxidizing agents such as hydrogen peroxide (H2O2) or the dopaminergic selective toxin 6-hydroxydopamine (6-OHDA) that is commonly used to model PD neurodegeneration. When neuroblastoma SH-SY5Y cells were pre-conditioned with 100% RAA-MSC media, then treated with H2O2 and 6-OHDA, mortality and ROS generation were reduced. We implemented the controlled release of RAA-MSC secretome from injectable biodegradable hydrogels that offer a possible in situ implant with mini-invasive techniques. The hydrogels were composed of type I bovine collagen (COLL) and low-molecular-weight hyaluronic acid (LMWHA) or COLL and polyethylene glycol (PEG). Hydrogels were suitable for RAA-MSC embedding up to 48h and secretome from these RAA-MSCs was active and counteracted 6-OHDA toxicity, with upregulation of the antioxidant enzyme sirtuin 3 (SIRT3). These results support a biomaterials-based approach for controlled delivery of MSC-produced neuroprotective factors in a PD-relevant experimental context.
Monocyte Distribution Width (MDW), a new cytometric parameter correlating with cytomorphologic changes occurring upon massive monocyte activation, has recently emerged as promising early biomarker of ...sepsis. Similar to sepsis, monocyte/macrophage subsets are considered key mediators of the life-threatening hyper-inflammatory disorder characterizing severe COVID-19. In this study, we longitudinally analyzed MDW values in a cohort of 87 COVID-19 patients consecutively admitted to our hospital, showing significant correlations between MDW and common inflammatory markers, namely CRP (p < 0.001), fibrinogen (p < 0.001) and ferritin (p < 0.01). Moreover, high MDW values resulted to be prognostically associated with fatal outcome in COVID-19 patients (AUC = 0.76, 95% CI: 0.66-0.87, sensitivity 0.75, specificity 0.70, MDW threshold 26.4; RR = 4.91, 95% CI: 1.73-13.96; OR = 7.14, 95% CI: 2.06-24.71). This pilot study shows that MDW can be useful in the monitoring of COVID-19 patients, as this innovative hematologic biomarker is: (1) easy to obtain, (2) directly related to the activation state of a fundamental inflammatory cell subset (i.e. monocytes, pivotal in both cytokine storm and sepsis immunopathogenesis), (3) well correlated with clinical severity of COVID-19-associated inflammatory disorder, and, in turn, (4) endowed with relevant prognostic significance. Additional studies are needed to define further the clinical impact of MDW testing in the management of COVID-19 patients.
Regulation of hematopoiesis during human development remains poorly defined. Here we applied single-cell RNA sequencing (scRNA-seq) and single-cell assay for transposase-accessible chromatin ...sequencing (scATAC-seq) to over 8,000 human immunophenotypic blood cells from fetal liver and bone marrow. We inferred their differentiation trajectory and identified three highly proliferative oligopotent progenitor populations downstream of hematopoietic stem cells (HSCs)/multipotent progenitors (MPPs). Along this trajectory, we observed opposing patterns of chromatin accessibility and differentiation that coincided with dynamic changes in the activity of distinct lineage-specific transcription factors. Integrative analysis of chromatin accessibility and gene expression revealed extensive epigenetic but not transcriptional priming of HSCs/MPPs prior to their lineage commitment. Finally, we refined and functionally validated the sorting strategy for the HSCs/MPPs and achieved around 90% enrichment. Our study provides a useful framework for future investigation of human developmental hematopoiesis in the context of blood pathologies and regenerative medicine.
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•The epigenetic and transcriptional landscape of human fetal hematopoiesis•Blood stem cells differentiate into three distinct oligopotent progenitor populations•Changes in motif accessibility in blood stem cells precede transcriptional priming•Refined sorting strategy to isolate and enrich for human fetal blood stem cells
Ranzoni et al. provide a detailed transcriptional and chromatin accessibility map of fetal liver and bone marrow hematopoietic stem cells (HSCs). Within HSCs, they revealed extensive epigenetic but not transcriptional priming. They identified transcriptional and functional differences between HSCs from liver and bone marrow.
Posttransplantation human herpesvirus-8 (HHV8)/Kaposi sarcoma herpesvirus (KSHV) primary infection and/or reactivations are associated with uncommon and sometimes fatal, neoplastic, and ...non-neoplastic diseases. HHV8-related clinical manifestations notably range from Kaposi sarcoma (KS) to either primary effusion lymphoma or multicentric Castleman disease B-cell malignancies, and from polyclonal HHV8-positive plasmacytic lymphoproliferative disorders to bone marrow failure and peripheral cytopenias, associated or not with hemophagocytic syndromes, and to acute hepatitis syndromes. We reviewed the patient series reported in the literature and summarized clinical management aspects, in terms of diagnosis, follow-up, and treatment. We described typical clinical presentations and histopathologic diagnostic features of these diseases, and we discussed the role of HHV8-specific serologic, molecular, and immunologic assays, particularly focusing on recent data from HHV8-specific T-cell monitoring in posttransplantation KS patients. We finally discussed actual therapeutic options, namely, the reduction or discontinuation of immunosuppressive therapy or the switch from calcineurin inhibitors to mTOR inhibitors, as alternatives to antineoplastic chemotherapy, along with the use of antiherpesvirus agents as prophylactic or therapeutic measures, and treatment with rituximab in posttrans-plantation multicentric Castleman disease patients and non-neoplastic HHV8-associated syndromes.
Nucleophosmin (
) gene mutations rarely occur in non-acute myeloid neoplasms (MNs) with <20% blasts. Among nearly 10,000 patients investigated so far, molecular analyses documented
mutations in ...around 2% of myelodysplastic syndrome (MDS) cases, mainly belonging to MDS with excess of blasts, and 3% of myelodysplastic/myeloproliferative neoplasm (MDS/MPN) cases, prevalently classified as chronic myelomonocytic leukemia. These uncommon malignancies are associated with an aggressive clinical course, relatively rapid progression to overt acute myeloid leukemia (AML) and poor survival outcomes, raising controversies on their classification as distinct clinico-pathologic entities. Furthermore, fit patients with
-mutated MNs with <20% blasts could benefit most from upfront intensive chemotherapy for AML rather than from moderate intensity MDS-directed therapies, although no firm conclusion can currently be drawn on best therapeutic approaches, due to the limited available data, obtained from small and mainly retrospective series. Caution is also suggested in definitely diagnosing
-mutated MNs with blast count <20%, since
-mutated AML cases frequently present dysplastic features and multilineage bone marrow cells showing abnormal cytoplasmic NPM1 protein delocalization by immunohistochemical staining, therefore belonging to
-mutated clone regardless of blast morphology. Further prospective studies are warranted to definitely assess whether
mutations may become sufficient to diagnose AML, irrespective of blast percentage.
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