Inflammation and immune responses after tissue injury play pivotal roles in the resolution of inflammation, tissue recovery, fibrosis, and remodeling. Regulatory T cells (Tregs) are responsible for immune tolerance and are usually activated in secondary lymphatic tissues. Activated Tregs subsequently regulate effector T cell and dendritic cell activation. For clinical applications such as the suppression of both autoimmune diseases and the rejection of transplanted organs, methods to generate stabilized antigen-specific Tregs are required. For this purpose, transcriptional and epigenetic regulation of Foxp3 expression has been investigated. In addition to conventional Tregs, there are some Tregs that reside in tissues and are called tissue Tregs. Tissue Tregs exhibit tissue-specific functions that contribute to the maintenance of tissue homeostasis and repair. Such tissue Tregs could also be useful for Treg-based cell therapy. We recently discovered brain Tregs that accumulate in the brain during the chronic phase of ischemic brain injury. Brain Tregs resemble other tissue Tregs, but are unique in expressing neural cell-specific genes such as the serotonin receptor (Htr7); consequently, brain Tregs respond to serotonin. Here, we describe our experiences in the use of Tregs to suppress graft-versus-host disease and to promote neural recovery after stroke.

Maintenance hemodialysis (HD) therapy is essential for survival in patients with end-stage renal disease (ESRD); however, HD can also be life-threatening in the final stages of ESRD. Currently, no clear indicators and/or biomarkers exist regarding when HD should be forgone. In the present study, we examined temporal changes in multiple clinical parameters, including biochemical data, physical data, the use of specific medical treatments, nursing care levels, and the activities of daily living (ADL) in 47 ESRD patients who underwent maintenance HD and who died in our hospital. We also investigated the status of informed consents regarding the forgoing of HD in these patients. We found that while biochemical parameters were unaltered, physical parameters such as consciousness levels and blood pressure gradually deteriorated during hospitalization. The use of the following specific medical treatments significantly increased over time: vasopressor use, O₂ inhalation, and ventilator use. The need for nursing care increased and the ADL levels decreased toward the time of death. Medical doctors gave information regarding forgoing HD to patients and/or their family/relatives in 55% of cases, obtained agreement to forego HD in 45% of cases, and HD was actually foregone in 38% of cases. Most clinical parameters were not significantly different between the patients whose HD sessions were forgone versus those in whom HD was continued, indicating that HD was foregone in the very last stages of life. The results suggest that physical parameters, the use of specific medical treatments, the levels of nursing care, and ADL are potential indicators for forgoing HD in the final stages of ESRD.