Yasumasa Kato

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of novel coronavirus disease 2019 (COVID-19), a major cause of atypical pneumonia worldwide. Elderly individuals and those with underlying illnesses, such as cardiovascular and pulmonary diseases, are at a high risk of experiencing severe symptoms and have high mortality rates. There is therefore a major need to develop additional vaccines, effective treatments, and complementary drugs to control this infection. Lactoferrin (LF), a naturally-occurring glycoprotein, is bioactive against viruses and other pathogens. LF has a unique immunomodulatory function and is indispensable for immunity in infants. It is thought to contribute to biological defense in individuals across all generations, not only infants. LF inhibits viral adhesion to host cell surfaces through ionic binding to glycosaminoglycans and/or specific binding to viral structures. Purified LF is cost-effective and orally available as a dietary supplement. Here, we review studies on the protective role of LF against common viral infections. Based on this review, we propose that LF can be a possible prophylactic or therapeutic agent for COVID-19 disease.

Endodontic–periodontal lesions (EPLs) are chronic inflammatory lesions in the mouth caused by multiple factors. Both periapical and marginal periodontitis are characterized by infection and inflammation around the affected teeth, suggesting that the theory of complex systems might describe the progression of EPL. The diagnosis and treatment of EPLs are complicated by variations of this condition and difficulties distinguishing EPLs from other diseases. Technological advances in diagnostic and treatment methods, including cone beam computed tomography, microscopy, mineral trioxide aggregates, and periodontal regenerative treatment, have improved outcomes, even in untreatable teeth. However, treating EPLs with iatrogenic problems and/or severe periodontitis remains challenging. Assessing the risk of each EPL based on the possible pathogenesis of each EPL is essential for determining individualized treatment and optimizing personalized medicine for individual patients.

With the spread of oral implant therapy, serious medical complications related to implant surgery are becoming a social problem. Although the number of complications after implant surgery in the edentulous jaw is decreasing in Japan, maxillary-sinus-related complications (MSRCs) have reached the highest number since 2012. It is essential to identify and eliminate possible predisposing risk factors for MSRCs at an early stage to prevent MSRCs. In this review article, we highlight the causal factors of postoperative complications with or without sinus augmentation for the maxillary molar region to achieve optimal treatment outcomes and reduce complications. In particular, we focus on anatomical variations that can cause the impairment of maxillary sinus drainage. Furthermore, we emphasize that the paradigm for personalized medicine for patients with a maxillary edentulous jaw by ENT specialist and dentist cooperation is shifting from the traditional assessment of maxillary sinus pathologies alone to the new assessment of anatomic variations that can cause the impairment of maxillary sinus drainage in addition to maxillary sinus pathologies.

Bovine lactoferrin (bLF) is a naturally occurring glycoprotein with antibacterial and antiviral activities. We evaluated whether bLF can prevent viral infections in the human intestinal epithelial cell line Caco-2. To assess antiviral responses, we measured the levels of interferon (IFN) expression, IFN-stimulated gene expression, and infection with a pseudotyped virus bearing either severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein or vesicular stomatitis virus (VSV)-G protein after treatment of cells with both bLF and polyinosinic-polycytidylic acid, an analog of double-stranded RNA that mimics viral infection. Combination treatment of cells with both bLF and polyinosinic-polycytidylic acid increased mRNA and protein expression of several IFN genes ( IFNB, IFNL1, and IFNL2) and IFN-stimulated genes ( ISG15, MX1, IFITM1, and IFITM3) in Caco-2 cells. However, treatment with bLF alone did not induce an antiviral response. Furthermore, combination treatment suppressed infection of the SARS-CoV-2 pseudotyped virus more efficiently than did bLF treatment alone, even though combination treatment increased the expression of mRNA encoding ACE2. These results indicate that bLF increases the antiviral response associated with the double-stranded RNA-stimulated signaling pathway. Our results also suggest that bLF and double-stranded RNA analogs can be used to treat viral infections, including those caused by SARS-CoV-2.

Letter for the article Risk Perception of Septic Shock with Multiple Organ Failure Due to Acute Exacerbation of an Infectious Dental Disease

Introduction and importance: It is difficult that doctors other than otorhinolaryngologist/radiologist find early postoperative maxillary cyst (POMC) because it tends to expand gradually with no symptoms over a period of years. Case presentation: A 60-year-old Japanese male who had previously undergone a bilateral Caldwell-Luc operation for the treatment of chronic sinusitis, experienced maxillary sinus floor elevation and implant placement. Eleven years after the implant placement, we discovered that the left POMC existed close to dental implants. Fortunately, dental implants still displayed proper osseointegration. Thus, the patient has been successfully treated for POMC, which had not been proper diagnosed before the implantation, by a marsupialization using nasal endoscopy and successfully preserved dental implant. Clinical discussion: Because the expanding POMC might result in dental implant failure after several years, we think that marsupialization is useful as a risk management for possible failure of dental implant close to POMC when it had not been found before maxillary sinus floor elevation and insertion of dental implant. Conclusion: Doctors should recognize that patients will have the risk of the dental implant failure after several years due to the expanding cyst when early POMC had not been diagnosed and treated properly before the implantation. Highlights:

Taste-2 receptors (TAS2Rs), which belong to the G-protein coupled receptor (GPCR) family, are receptors for bitter taste perception. The aim of this study was to investigate whether zinc deficiency affects the expression of TAS2R genes. The promoter activity of the TAS2R7, TAS2R8, and TAS2R42 genes were determined in Ca9-22 oral squamous cell carcinoma cells cultured in the presence or absence of zinc. Luciferase reporter assays showed that zinc deprivation inhibited TAS2R8 promoter activity, but not the promoter activity of the other two genes. Treatment of the cells with N,N,N’,N’-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN), an intracellular chelator of Zn²⁺, in the presence of 10% fetal bovine serum reduced TAS2R8 promoter activity. Truncation/deletion mutants of TAS2R8 promoter-luciferase constructs showed that the region from nucleotide −1152 to nucleotide −925 was critical for intracellular zinc dependency and contained a CCCTC-binding factor (CTCF) binding motif. A chromatin immunoprecipitation (ChiP) assay showed that CTCF bound specifically to this region, a binding abrogated by zinc deficiency, suggesting that CTCF plays a critical role in zinc-dependent bitter taste perception through TAS2R8.