SummaryEmbryonic stem cells hold great promise for various diseases because of their unlimited capacity for self-renewal and ability to differentiate into any cell type in the body. However, despite over 3 decades of research, there have been no reports on the safety and potential efficacy of pluripotent stem cell progeny in Asian patients with any disease. Here, we report the safety and tolerability of subretinal transplantation of human embryonic-stem-cell (hESC)-derived retinal pigment epithelium in four Asian patients: two with dry age-related macular degeneration and two with Stargardt macular dystrophy. They were followed for 1 year. There was no evidence of adverse proliferation, tumorigenicity, ectopic tissue formation, or other serious safety issues related to the transplanted cells. Visual acuity improved 9–19 letters in three patients and remained stable (+1 letter) in one patient. The results confirmed that hESC-derived cells could serve as a potentially safe new source for regenerative medicine.
The authors experienced a case with ocular ischemia with hypotony following injection of a dermal filler for augmentation rhinoplasty. Immediately after injection, the patient demonstrated a permanent visual loss with typical fundus features of central retinal artery occlusion. Multiple crusted ulcerative patches around the nose and left periorbit developed, and the left eye became severely inflamed, ophthalmoplegic, and hypotonic. Signs of anterior and posterior segment ischemia were observed including severe cornea edema, iris atrophy, and chorioretinal swelling. The retrograde arterial embolization of hyaluronic acid gel from vascular branches of nasal tip to central retinal artery and long posterior ciliary artery was highly suspicious. After 6 months of follow up, skin lesions and eyeball movement became normalized, but progressive exudative and tractional retinal detachment was causing phthisis bulbi.
By virtue of minimum invasiveness and driving ability using a magnetic field, drug delivery with the aid of a microrobot has an inherent potential for targeted treatment for the eye. The use of microrobots, however, has the limitation of leaving magnetic nanoparticles (MNPs) in the eye that can cause side effects. In this study, a bilayer hydrogel microrobot capable of retrieving MNPs after drug delivery is proposed that overcomes the limitations of existing microrobots. The bilayer hydrogel microrobot is composed of an MNPs layer and a therapeutic layer. Upon applying an alternating magnetic field (AMF) at the target point, the therapeutic layer is dissolved to deliver drug particles, and then the MNPs layer can be retrieved using a magnetic field. The targeting and MNPs retrieval tests validate the drug delivery and MNPs retrieval ability of the microrobot. The ex vivo bovine vitreous and in vitro cell tests demonstrate the potential for the vitreous migration of the microrobot and the therapeutic effect against retinoblastoma Y79 cancer cells. This bilayer hydrogel sheet‐type intraocular microrobot provides a new drug delivery paradigm that overcomes the limitations of microrobot by maintaining the advantages of conventional microrobots in delivering drugs to the eye and retrieving MNPs after drug delivery.
Diabetic retinopathy (DR) is the leading cause of blindness in working-age people. Pericyte loss is one of the pathologic cellular events in DR, which weakens the retinal microvessels. Damage to the microvascular networks is irreversible and permanent; thus further progression of DR is inevitable. In this study, we hypothesize that multipotent perivascular progenitor cells derived from human embryonic stem cells (hESC-PVPCs) improve the damaged retinal vasculature in the streptozotocininduced diabetic rodent models. We describe a highly efficient and feasible protocol to derive such cells with a natural selection method without cell-sorting processes. As a cellular model of pericytes, hESC-PVPCs exhibited marker expressions such as CD140B, CD146, NG2, and functional characteristics of pericytes. Following a single intravitreal injection into diabetic Brown Norway rats, we demonstrate that the cells localized alongside typical perivascular regions of the retinal vasculature and stabilized the blood-retinal barrier breakdown. Findings in this study highlight a therapeutic potential of hESCPVPCs in DR by mimicking the role of pericytes in vascular stabilization. STEM CELLS TRANSLATIONAL MEDICINE 2016;5:1268-1276
SIGNIFICANCEThis study provides a simple and feasible method to generate perivascular progenitor cells from human embryonic stem cells. These cells share functional characteristics with pericytes, which are irreversibly lost at the onset of diabetic retinopathy. Animal studies demonstrated that replenishing the damaged pericytes with perivascular progenitor cells could restore retinal vascular integrity and prevent fluid leakage. This provides promising and compelling evidence that perivascular progenitor cells can be used as a novel therapeutic agent to treat diabetic retinopathy patients.
Abstract-This paper presents an online controller for tracking power-budgets in multicore processors using dynamic voltage-frequency scaling. The proposed control law comprises an integral controller whose gain is adjusted online based on the derivative of the power-frequency relationship. The control law is designed to achieve rapid settling time, and its tracking property is formally proven. Importantly, the controller design does not require off-line analysis of application workloads making it feasible for emerging heterogeneous and asymmetric multicore processors. Simulation results are presented for controlling power dissipation in multiple cores of an asymmetric multicore processor. Each core is i) equipped with the controller, ii) assigned a power budget, and iii) operates independently in tracking to its power budget. We use a cycle-level multicore simulator driven by traces from SPEC2006 benchmarks demonstrating that the proposed algorithm achieves a faster settling time than examples of a static setting of the controller gain.
Patients with fewer ethmoid air cell septa and a larger lamina papyracea area per septum are more likely to develop medial wall fractures than inferior wall fractures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.