Concealed hypothyroidism in patients with myeloperoxidase antineutrophili cytoplasmic autoantibodies- (MPO-ANCA) positive renal disease.

AIM: To elucidate the relationship between thyroid disorders and myeloperoxidase (MPO) antineutrophili cytoplasmic autoantibodies-(ANCA) positive renal disease, we investigated the prevalence of thyroid diseases in patients with them. SUBJECTS AND METHODS: The subjects consisted of 10 patients (6 males and 4 females) diagnosed as having MPO-ANCA-positive renal disease in our hospital. To evaluate thyroid function, serum thyroid-stimulating hormone (TSH) and free-thyroxine (FT4) levels were measured by a immunoradiometric assay (IRMA) and a radioimmunoassay (RIA), respectively. Thyroid autoantibodies against microsomal antigen and thyroglobulin were measured by means of particle agglutination. In addition, antibodies against thyroid peroxidase (TPO-Ab) and purified thyroglobulin (Tg-Ab) were also determined by RIA. To assess the disease activity, we employed Birmingham Vasculitis Activity Score (BVAS). RESULTS: The results were that 4 out of 10 patients (40%) were accompanied by hypothyroidism, including 2 patients with subclinical hypothyroidism and I during thyroid hormone replacement therapy. The BVAS of the hypothyroidism group (group A) was significantly lower (p < 0.05) than that of non-hypothyroidism group (group B), 18.5 +/- 9.0 (mean +/- SD) versus 24.2 +/- 16.6. MPO-ANCA titers were not significant between the two groups, 376.8 +/- 316.8 EU versus 311.5 +/- 203.6 EU. CONCLUSION: Thyroid disorder, especially hypothyroidism would not be a rare complication in patients with MPO-ANCA-positive renal disease. We should concentrate more on thyroid lesion in them.     

Prevention Measures for COVID-19 and Changes in Kawasaki Disease Incidence

BackgroundKawasaki disease is suspected to be triggered by previous infection. The prevention measures for coronavirus disease 2019 (COVID-19) have reportedly reduced transmission of certain infectious diseases. Under these circumstances, the prevention measures for COVID-19 may reduce the incidence of Kawasaki disease.MethodsWe conducted a retrospective study using registration datasets of patients with Kawasaki disease who were diagnosed in all 11 inpatient pediatric facilities in Yamanashi Prefecture. The eligible cases were 595 cases that were diagnosed before the COVID-19 pandemic (from January 2015 through February 2020) and 38 cases that were diagnosed during the COVID-19 pandemic (from March through November 2020). Incidence of several infectious disease were evaluated using data from the Infectious Disease Weekly Report conducted by the National Institute of Infectious Diseases.ResultsEpidemics of various infectious diseases generally remained at low levels during the first 9 months (March through November 2020) of the COVID-19 pandemic. Moreover, the incidence of COVID-19 was 50–80 times lower than the incidence in European countries and the United States. The total number of 38 cases with Kawasaki disease for the 9 months during the COVID-19 pandemic was 46.3% (−3.5 standard deviations [SDs] of the average [82.0; SD, 12.7 cases] for the corresponding 9 months of the previous 5 years. None of the 38 cases was determined to be triggered by COVID-19 based on their medical histories and negative results of severe acute respiratory syndrome coronavirus 2 testing at admission.ConclusionThese observations provide a new epidemiological evidence for the notion that Kawasaki disease is triggered by major infectious diseases in children.Key words: COVID-19, Kawasaki disease, retrospective database, infectious disease     

The antirheumatic drug leflunomide inhibits osteoclastogenesis by interfering with receptor activator of NF‐κB ligand–stimulated induction of nuclear factor of activated T cells c1

Objective

Suppression of bone destruction is required as part of an effective therapeutic strategy for autoimmune arthritis. Although numerous antirheumatic drugs are in clinical use, little is known about whether they inhibit bone destruction by acting on activated T cells or other cell types, such as bone‐resorbing osteoclasts. This study was undertaken to determine whether leflunomide has a direct action on the osteoclast lineage and to gain insights into the molecular basis for the bone‐protective effect of leflunomide.

Methods

The direct effect of leflunomide on osteoclast differentiation was investigated using an in vitro culture system of bone marrow monocyte/macrophages stimulated with receptor activator of NF‐κB ligand (RANKL) and macrophage colony‐stimulating factor. The molecular mechanism of the inhibition was analyzed by genome‐wide screening. The T cell–independent effect of leflunomide was examined in rag‐2^−/− mice.

Results

Leflunomide blocked de novo pyrimidine synthesis and RANKL‐induced calcium signaling in osteoclast precursor cells in vitro; hence, the induction of nuclear factor of activated T cells c1 (NF‐ATc1) was strongly inhibited. The inhibition of this pathway is central to the action of leflunomide, since the inhibition was overcome by ectopic expression of NF‐ATc1 in the precursor cells. Leflunomide suppressed endotoxin‐induced inflammatory bone destruction even in rag‐2^−/− mice.

Conclusion

Leflunomide has a direct inhibitory effect on RANKL‐mediated osteoclast differentiation by inhibiting the induction of NF‐ATc1, the master switch regulator for osteoclast differentiation. Our study suggests that the direct inhibitory action of leflunomide on osteoclast differentiation constitutes an important aspect in the amelioration of bone destruction, and that the RANKL‐dependent NF‐ATc1 induction pathway is a promising target for pharmacologic intervention in arthritic bone destruction.

     

Tropism of SARS-CoV-2 for human cortical astrocytes

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) readily infects a variety of cell types impacting the function of vital organ systems, with particularly severe impact on respiratory function. Neurological symptoms, which range in severity, accompany as many as one-third of COVID-19 cases, indicating a potential vulnerability of neural cell types. To assess whether human cortical cells can be directly infected by SARS-CoV-2, we utilized stem-cell-derived cortical organoids as well as primary human cortical tissue, both from developmental and adult stages. We find significant and predominant infection in cortical astrocytes in both primary tissue and organoid cultures, with minimal infection of other cortical populations. Infected and bystander astrocytes have a corresponding increase in inflammatory gene expression, reactivity characteristics, increased cytokine and growth factor signaling, and cellular stress. Although human cortical cells, particularly astrocytes, have no observable ACE2 expression, we find high levels of coronavirus coreceptors in infected astrocytes, including CD147 and DPP4. Decreasing coreceptor abundance and activity reduces overall infection rate, and increasing expression is sufficient to promote infection. Thus, we find tropism of SARS-CoV-2 for human astrocytes resulting in inflammatory gliosis-type injury that is dependent on coronavirus coreceptors.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the life-threatening illness COVID-19 and is responsible for a global pandemic resulting in more than 5.8 million deaths worldwide. Although SARS-CoV-2 infection can cause catastrophic, life-threatening damage to respiratory function, the capacity to infect other cell types and disrupt function of additional organ systems is a subject of intense study. Strikingly, many patients suffering with or having recovered from COVID-19 present with a range of neurological symptoms including seizures; encephalopathy; stroke; headaches; dizziness; short-term memory loss; loss of smell and taste; confusion; a general inability to focus; and new or recurring neuropsychiatric symptoms, like anxiety and depression (1–5). As many as one-third of individuals, 6 mo after recovering from COVID-19 infection, are diagnosed with neurological or neuropsychiatric conditions (6). Additionally, individuals with mental health diagnoses are more susceptible to coronavirus infection and have impaired long-term health outcomes (7).It is unclear whether the range of neurological symptoms are a result of direct infection of the neural tissue or a secondary consequence of widespread inflammation downstream of viral infection in other tissues. Several studies have demonstrated how inflammation contributes to systemic problems in a variety of organ systems, including the central nervous system (CNS) (8, 9). However, SARS-CoV-2 can infect neurons in the nasal epithelium, a potential mode of entry to the CNS from the periphery, and the presence of viral RNA has been detected in neural tissues in patients (10). Recent studies report mixed findings regarding the presence of coronavirus viral RNA and antibodies in the cerebral spinal fluid (CSF) of COVID-19 patients (3, 8, 11, 12). However, choroid plexus organoids containing the cell type that produces CSF can be readily infected by SARS-CoV-2 in vitro (13, 14), suggesting possible viral access to CSF. Additionally, the virus can infect and disrupt brain vasculature. Studies of postmortem brain tissue from severely infected COVID-19 patients have reported widespread inflammation in the brainstem, choroid plexus, and brain parenchyma characterized by infiltration of immune cells including microglia and T cells, as well as infection of cranial nerves, microvascular injury, fibrinogen leakage, and extensive astrogliosis (8, 15, 16). Together, these studies suggest the capacity for viral transmission into the CNS through leaky vasculature, the nasal epithelium, and/or CSF.The vulnerability of particular cell types in the brain and the impact on neurological health and function require in-depth study, and human stem-cell-derived neural models have been utilized to evaluate viral tropism (17, 18). Studies of cerebral organoids, which are reflective of developmental stages, suggest that in vitro neurons may be vulnerable to SARS-CoV-2 infection. However, reports regarding susceptibility of neurons from different brain regions have been mixed across organoid studies (13, 14, 19). Recently, studies have begun to explore the vulnerability of nonneuronal populations, including vascular pericytes and glial cells, using stem-cell-derived organoid and assembloid models (20, 21). Additionally, studies exploring the loss of smell identified viral tropism of nonneural support cells and vascular cells in the olfactory epithelium (22). Here, we utilized primary cortical tissue from both the developing and the adult brain, paired with cortical organoid models across neurogenic and gliogenic stages, to evaluate which human neural cell types can be directly infected by SARS-CoV-2 and at what stages of maturation. In primary cortical tissue cultures and cortical organoids exposed to SARS-CoV-2, we observed significant infection and viral replication in immature and mature astrocytes but minimal infection in other neural cell types. As a response to infection, we observed widespread inflammation, cytokine secretion, and reactivity in astrocytes. However, cortical astrocytes do not express observable levels of ACE2, the canonical SARS-CoV-2 receptor, suggesting that the virus may use another means of entry. We observed that SARS-CoV-2 cofactors CD147 and DPP4 are highly expressed in infected astrocytes. Reducing the abundance of CD147 or the activity of DPP4 reduced infection, whereas increasing expression of these receptors promoted infection, suggesting a role in viral entry or propagation. Our study provides evidence of SARS-CoV-2 tropism for human astrocytes with implications for the cellular vulnerability of the human brain and downstream consequences to neurological function.     

A novel potent inhibitor of inducible nitric oxide synthase, ONO-1714, reduces hyperoxic lung injury in mice

STUDY OBJECTIVES: High-concentration oxygen therapy is used to treat tissue hypoxia, but hyperoxia causes lung injury. Overproduction of nitric oxide by nitric oxide synthase (NOS) is thought to promote hyperoxic lung injury. The present study was conducted to examine the role of inducible nitric oxide synthase (iNOS) in hyperoxic lung injury in mice. MEASUREMENTS AND RESULTS: Mice were exposed to >98% oxygen for 72 h, and ONO-1714 (0.05 mg/kg) (ONO) was subcutaneously administered to block iNOS. Hyperoxia significantly increased total cell count, protein concentration, and nitrites/nitrates in the bronchoalveolar lavage fluid and proinflammatory cytokines in the lung tissue. ONO significantly prevented the increases in all of these variables. ONO suppressed histologic evidence of lung injury. ONO markedly inhibited iNOS protein expression and nitrotyrosine production in lung homogenates. After exposure to hyperoxia, alveolar epithelial cells stained positively for 8-hydroxy-2'-deoxyguanosine, a proper marker of oxidative DNA damage by reactive oxygen species. ONO attenuated this finding. CONCLUSIONS: NOS play important roles in the pathogenesis of hyperoxic lung injury. Selective iNOS inhibitors may be useful for the treatment of hyperoxic lung injury.     

Ten‐year experience of recombinant activated factor VII use in surgical patients with congenital haemophilia with inhibitors or acquired haemophilia in Japan

Patients with congenital haemophilia with inhibitors or acquired haemophilia are at risk of bleeding complications during surgery. In these patients, replacement therapy for the missing coagulation factor is ineffective, and a bypassing agent such as recombinant activated factor VII (rFVIIa) is required to manage bleeding. To evaluate the safety and haemostatic efficacy of rFVIIa treatment in Japanese patients with congenital haemophilia with inhibitors to FVIII/FIX or acquired haemophilia undergoing surgery. Postmarketing surveillance data from May 2000 to March 2010 were analysed to assess the haemostatic efficacy of 38 procedures in 22 patients with congenital haemophilia A, 13 procedures in seven patients with congenital haemophilia B, and five procedures in five patients with acquired haemophilia. Postoperative bleeding control was judged to be effective (bleeding was stopped completely or reduced considerably) for 34/38 procedures (89%) in patients with congenital haemophilia A, 10/13 procedures (77%) in patients with congenital haemophilia B, and 4/5 procedures (80%) in patients with acquired haemophilia. Tranexamic acid was used concomitantly for 36/56 procedures (64%). Safety was analysed for 66 procedures in 37 patients. Adverse effects potentially related to rFVIIa treatment included mild superficial thrombophlebitis, mild decrease in platelet count, and mild elevation of the serum alanine transaminase level in one patient each. All adverse effects resolved without treatment. Administration of rFVIIa provided adequate haemostasis without serious adverse effects in the majority of cases. The efficacy and safety data in Japanese patients were similar to previously published data from other countries.