Post-stroke treatment with argon preserved neurons and attenuated microglia/macrophage activation long-termly in a rat model of transient middle cerebral artery occlusion (tMCAO)

In a previous study from our group, argon has shown to significantly attenuate brain injury, reduce brain inflammation and enhance M2 microglia/macrophage polarization until 7 days after ischemic stroke. However, the long-term effects of argon have not been reported thus far. In the present study, we analyzed the underlying neuroprotective effects and potential mechanisms of argon, up to 30 days after ischemic stroke. Argon administration with a 3 h delay after stroke onset and 1 h after reperfusion demonstrated long-term neuroprotective effect by preserving the neurons at the ischemic boundary zone 30 days after stroke. Furthermore, the excessive microglia/macrophage activation in rat brain was reduced by argon treatment 30 days after ischemic insult. However, long-lasting neurological improvement was not detectable. More sensorimotor functional measures, age- and disease-related models, as well as further histological and molecular biological analyses will be needed to extend the understanding of argon’s neuroprotective effects and mechanism of action after ischemic stroke.

C-Reactive Protein Knockout Attenuates Temporomandibular Joint Inflammation in Rats

Background. C-reactive protein (CRP), a biomarker of inflammation, is highly expressed in osteoarthritis- (OA-) related diseases, but its exact role remains unknown. In this study, we evaluated the biological effect of CRP on temporomandibular joint (TMJ) inflammation. Methods. Freund’s complete adjuvant (CFA) was used to induce TMJ inflammation in CRP-knockout (CRP-/-) and control rats. Degenerative changes in the TMJ were compared to elucidate the role of CRP in TMJ inflammation. In addition, inflammatory cytokines, macrophage activation, and osteoclast differentiation were evaluated by real-time quantitative polymerase chain reaction, immunohistochemistry, and tartrate-resistant phosphatase staining to explore the potential regulatory mechanism. Results. Compared to the control, CFA induced TMJ inflammation, which increased systemic and local CRP expression. Furthermore, CRP-/- rats exhibited less severe inflammatory symptoms. The downregulation of proinflammatory cytokines (interleukin- (IL-) 1β and IL-6) and upregulation of the anti-inflammatory cytokine IL-10 were detected in CRP-/- rats, which also exhibited reduced macrophage activation and osteoclast differentiation. Conclusion. These results indicated that controlling the highly elevated levels of CRP during inflammation could modify the cytokine profile, macrophage activation, and osteoclast differentiation, thus, providing beneficial effects for TMJ-OA prevention and treatment.

Lyz2-Cre-Mediated Genetic Deletion of Septin7 Reveals a Role of Septins in Macrophage Cytokinesis and Kras-Driven Tumorigenesis

By crossing septin7-floxed mice with Lyz2-Cre mice carrying the Cre recombinase inserted in the Lysozyme-M (Lyz2) gene locus we aimed the specific deletion of septin7 in myeloid cells, such as monocytes, macrophages and granulocytes. Septin7flox/flox:Lyz2-Cre mice show no alterations in the myeloid compartment. Septin7-deleted macrophages (BMDMs) were isolated and analyzed. The lack of Septin7 expression was confirmed and a constitutive double-nucleation was detected in Septin7-deficient BMDMs indicating a defect in macrophage cytokinesis. However, phagocytic function of macrophages as judged by uptake of labelled E. coli particles and LPS-stimulated macrophage activation as judged by induction of TNF mRNA expression and TNF secretion were not compromised. In addition to myeloid cells, Lyz2-Cre is also active in type II pneumocytes (AT2 cells). We monitored lung adenocarcinoma formation in these mice by crossing them with the conditional knock-in Kras-LSL-G12D allele. Interestingly, we found that control mice without septin7 depletion die after 3–5 weeks, while the Septin7-deficient animals survived 11 weeks or even longer. Control mice sacrificed in the age of 4 weeks display a bronchiolo-alveolar hyperplasia with multiple adenomas, whereas the Septin7-deficient animals of the same age are normal or show only a weak multifocal brochiolo-alveolar hyperplasia. Our findings indicate an essential role of Septin7 in macrophage cytokinesis but not in macrophage function. Furthermore, septin7 seems absolutely essential for oncogenic Kras-driven lung tumorigenesis making it a potential target for anti-tumor interventions.

Sézary syndrome preceded by mycosis fungoides and complicated by tumor lysis syndrome and macrophage activation syndrome

Sir, Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common malignancies of cutaneous T-cell lymphoma [1]. Herein, we report a case of SS complicated by tumor lysis syndrome and macrophage activation syndrome. A 54-year-old patient, followed since October 2017 for mycosis fungoides and undergoing various treatments (PUVA therapy, methotrexate, chlorambucil + prednisone), presented with an aggravation of lesions toward extensive and intensely pruritic. A clinical examination revealed dry erythroderma, scratch marks, wart plaques, an accentuation of frontal wrinkles and nasolabial folds (leonine facies), palmoplantar fissuring keratoderma, xanthopachyonychia of all nails, and a carapace-like appearance of the scalp (Figs. 1 – 3). Generalized lymphadenopathy, hepatomegaly, and a state of anasarca-type edema caused by hypoalbuminemia were also found. A skin biopsy revealed lymphoproliferation of CD4+ T-cells and an aberrant loss of pan-T antigens. The CD4-to-CD8 ratio was at 48.5% and Sézary cells were 6960 (absolute value). A lymph node biopsy showed a dense infiltration of Sézary cells. A PET scan revealed hypermetabolism in the entire skin and at the lymph node level. Tumor lysis syndrome was evident, with high levels of blood uric acid (at 182 mg/L), elevated LDH (at 924 U/L), and functional kidney failure. Macrophage activation syndrome was also present, with fever, anemia and thrombocytopenia, liver cytolysis, hypertriglyceridemia, and hyperferritinemia. The patient received an albumin infusion, oral corticosteroid therapy to treat the syndrome, and rasburicase for hyperuremia. Despite this, the patient died before multiagent chemotherapy could have been started. On rare occasions, SS may be preceded by a prior history of classic MF. The International Society for Cutaneous Lymphomas (ISCL) recommends that such cases be designated “SS preceded by MF” [2]. Traditionally, SS is defined as a leukemic form of CTCL associated with erythroderma. Sézary cells are a population of large lymphocytes in the peripheral blood, with grooved and lobulated nuclei, in the case of SS, numbering 1000 cells/mL or more [2]. The histopathologic findings in the skin often resemble those observed in MF, with less prominent epidermotropism. As in MF, immunohistochemical studies showing a CD4 predominance and loss of pan-T-cell markers may be helpful. Lymph node involvement is characterized by the complete effacement of the nodal architecture by the infiltrating Sézary cells (2). The poor prognostic factors in Sézary syndrome include an advanced stage of the disease, an older age at onset, and large cell transformation [3]. While high response rates may be achieved with systemic chemotherapy, they are frequently short-lived and associated with significant toxicities [2]. The management of SS is complicated and requires multidisciplinary collaboration between dermatologists, hematologists, biologists, and reanimators.