Masashi Kondo

Regenerative medicine in ophthalmology that uses induced pluripotent stem cells (iPS) cells has been described, but those studies used iPS cells derived from fibroblasts. Here, we generated iPS cells derived from iris cells that develop from the same inner layer of the optic cup as the retina, to regenerate retinal nerves. We first identified cells positive for p75NTR, a marker of retinal tissue stem and progenitor cells, in human iris tissue. We then reprogrammed the cultured p75NTR-positive iris tissue stem/progenitor (H-iris stem/progenitor) cells to create iris-derived iPS (H-iris iPS) cells for the first time. These cells were positive for iPS cell markers and showed pluripotency to differentiate into three germ layers. When H-iris iPS cells were pre-differentiated into neural stem/progenitor cells, not all cells became positive for neural stem/progenitor and nerve cell markers. When these cells were pre-differentiated into neural stem/progenitor cells, sorted with p75NTR, and used as a medium for differentiating into retinal nerve cells, the cells differentiated into Recoverin-positive cells with electrophysiological functions. In a different medium, H-iris iPS cells differentiated into retinal ganglion cell marker-positive cells with electrophysiological functions. This is the first demonstration of H-iris iPS cells differentiating into retinal neurons that function physiologically as neurons.

Favipiravir is an oral broad-spectrum inhibitor of viral RNA-dependent RNA polymerase that is approved for treatment of influenza in Japan. We conducted a prospective, randomized, open-label, multicenter trial of favipiravir for the treatment of COVID-19 at 25 hospitals across Japan. Eligible patients were adolescents and adults admitted with COVID-19 who were asymptomatic or mildly ill and had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. Patients were randomly assigned at a 1:1 ratio to early or late favipiravir therapy (in the latter case, the same regimen starting on day 6 instead of day 1). The primary endpoint was viral clearance by day 6. The secondary endpoint was change in viral load by day 6. Exploratory endpoints included time to defervescence and resolution of symptoms. Eighty-nine patients were enrolled, of whom 69 were virologically evaluable. Viral clearance occurred within 6 days in 66.7% and 56.1% of the early and late treatment groups (adjusted hazard ratio [aHR], 1.42; 95% confidence interval [95% CI], 0.76 to 2.62). Of 30 patients who had a fever (≥37.5°C) on day 1, times to defervescence were 2.1 days and 3.2 days in the early and late treatment groups (aHR, 1.88; 95% CI, 0.81 to 4.35). During therapy, 84.1% developed transient hyperuricemia. Favipiravir did not significantly improve viral clearance as measured by reverse transcription-PCR (RT-PCR) by day 6 but was associated with numerical reduction in time to defervescence. Neither disease progression nor death occurred in any of the patients in either treatment group during the 28-day participation. (This study has been registered with the Japan Registry of Clinical Trials under number jRCTs041190120.).

BACKGROUND: There is limited understanding of the characteristics of coronavirus disease 2019 (COVID-19) patients requiring hospitalization in Japan. METHODS: This study included 2638 cases enrolled from 227 health care facilities that participated in the COVID-19 Registry Japan (COVIREGI-JP). The inclusion criteria for enrollment of a case in COVIREGI-JP are both (1) a positive SARS-CoV-2 test and (2) inpatient treatment at a health care facility. RESULTS: The median age of hospitalized patients with COVID-19 was 56 years (interquartile range [IQR]: 40-71). More than half of the cases were male (58.9%, 1542/2619). Nearly 60% of the cases had close contact to confirmed or suspected cases of COVID-19. The median duration of symptoms before admission was 7 days (IQR: 4-10). The most common comorbidities were hypertension (15%, 396/2638) and diabetes without complications (14.2%, 374/2638). The number of non-severe cases (68.2%, n=1798) was twice the number of severe cases (31.8%, n=840) at admission. The respiratory support during hospitalization includes those who received no oxygen support (61.6%, 1623/2636), followed by those who received supplemental oxygen (29.9%, 788/2636), and IMV/ECMO (mechanical ventilation or extracorporeal membrane oxygenation) (8.5%, 225/2636). Overall, 66.9% (1762/2634) of patients were discharged home, while 7.5% (197/2634) died. CONCLUSIONS: We identified the clinical epidemiological features of COVID-19 in hospitalized patients in Japan. When compared with existing inpatient studies in other countries, these results demonstrated less comorbidities and a trend towards lower mortality.

Background: Intravenous administration of magnesium with a short hydration regimen is recommended for patients receiving high-dose cisplatin to protect against cisplatin-induced nephrotoxicity. However, the optimal dose of magnesium supplementation has not been clarified. The aim of this trial was to investigate the safety and efficacy of a short hydration regimen with 20 mEq of magnesium supplementation for lung cancer patients receiving cisplatin-based chemotherapy. Methods: The key eligibility criteria included cytologically or histologically diagnosed lung cancer, candidacy for cisplatin-based (≥ 60 mg/m2) chemotherapy or chemoradiotherapy, no prior chemotherapy, aged 20–75 years, and adequate renal function. Cisplatin was administered with pre-hydration with 20 mEq of magnesium sulfate. Mannitol was administered just before cisplatin infusion to enforce diuresis. The primary endpoint was the proportion of patients who underwent cisplatin-based chemotherapy with a short hydration regimen with 20 mEq of magnesium supplementation without a grade 2 or higher elevation in creatinine. Results: Forty patients with a median age of 66 years (range 35–74) were prospectively enrolled. Median baseline creatinine was 0.71 mg/dL. Median dose of cisplatin in the first cycle was 80 mg/m2. In the first cycle, no patients developed grade 2 creatinine toxicity. During the treatment period, one patient developed grade 2 creatinine elevation; thus, the proportion of patients without a grade 2 or higher elevation in creatinine was 97.5% (95% confidence interval 86.8–99.9). Conclusion: A short hydration regimen with 20 mEq of magnesium supplementation is safe and feasible for patients with lung cancer receiving cisplatin-based chemotherapy.

Atopic cataracts develop under the ages of 40 years, after which visual acuity rapidly declines. However, the mechanism underlying the development of atopic cataracts is not yet clear. We focused on the eosinophil granule major basic protein (MBP), which was detected in the aqueous humor of atopic cataracts previously, and which was cytotoxic. Specifically, we investigated its origin in this fluid and its effects on lens epithelial cells (LECs). MBP immunostaining was positive in atopic cataract-derived LECs, but negative in age-related cataract-derived LECs. MBP mRNA was not detected in either type of cataract, but protein was detected in the aqueous humor. Furthermore, the flare values associated with atopic cataracts were higher than those with age-related cataracts. When MBP was purified from eosinophils or recombinant MBP was added to LEC culture medium, cell viability decreased in a concentration-dependent manner, but an MBP antibody neutralized the cytotoxic effect of this protein towards these cells. These results were consistent with the flow of MBP into the aqueous humor from the blood due to a compromised blood–aqueous barrier. Thus, MBP could further penetrate the lens capsule and adhere to LECs, resulting in decreased cell viability and the development of atopic cataracts.

Dendritic cell-based immunotherapy, which uses a patient's own immune cells, can be used for cancer treatment and allergy control, such as autoimmune disease and rejection associated with transplantation. However, these treatments create a burden on patients due to repeated blood collection. We used cell biological analysis of monocytes with few mutations obtained from minimal blood collection for genome recombination. Next, we established human peripheral blood monocyte-derived induced pluripotent stem cells (iPSCs) using a commercial vector and standard culture method. We found that when established iPSCs were induced to differentiate, monocytes showed phagocytic properties and expressed CD14 and CX3CR1. Further, the generated dendritic cells (DCs) expressed CCL17 and highly expressed HLA-DR following the addition of the mite antigen. Taken together, these data show that monocyte-derived iPS cells can be used to differentiate into monocytes and DCs. In addition, the use of these cells can be applied to the pathological analysis of dendritic cell therapy and monocyte diseases.

末梢血を用いたiPS細胞作出において、これまでリンパ球が用いられ、単球と市販ベクターを用いて作出することはできなかった。我々は細胞生物学的見地から、末梢血単球の短期浮遊培養とiPS細胞へのリプログラミング法を新規開発した。作出された単球由来iPS細胞は、三胚葉への多分化能を有しており、単球、マクロファージおよび複数の抗原に反応性を有する樹状細胞に分化誘導できた。今後、さまざまな抗原に対する免疫寛容細胞への効率的な分化誘導法を検討し、自己免疫疾患に対する自己細胞療法の開発をめざしたい。(著者抄録)