Biocompatibility and functionality of a tissue-engineered living corneal stroma transplanted in the feline eye

PURPOSE. Corneal tissue shortage has become a major concern worldwide, which has motivated the search for alternative solutions to eye bank human eyes for corneal transplantation. Minimally invasive lamellar transplantation and tissue engineering may offer new opportunities for the rehabilitation of diseased corneas. The aim of this study was to evaluate the biocompatibility and functionality of stromal lamellar grafts tissue-engineered (TE) in vitro and transplanted in vivo in the cornea of a feline model. METHODS. The corneal stromas were engineered in culture from corneal stromal cells using the self-assembly approach, without the addition of exogenous material or scaffold. Eight healthy animals underwent two intrastromal grafts in one eye and the contralateral eye was used as a control. Animals were followed with slit-lamp ophthalmic examination, corneal esthesiometry and optical coherent tomography. Confocal microscopy, immunofluorescence, histology, and transmission electron microscopy (TEM) were performed at 4 months. RESULTS. Four months after transplantation, the TE-stromal grafts were transparent, functional, and well tolerated by the eye. All grafts remained avascular, with no signs of immune rejection, despite a short course of low-dose topical steroids. Corneal sensitivity returned to preoperative level and reinnervation of the grafts was confirmed by confocal microscopy and immunofluorescence. Histology and TEM of the TE-grafts showed a lamellar stromal structure with regular collagen fibril arrangement. CONCLUSIONS. These results open the way to an entirely new therapeutic modality. Intracorneal filling using a biocompatible, transparent, and malleable TE-stroma could be the basis for multiple types of novel therapeutic options in corneal interventional surgery

Relentless placoid chorioretinitis: A review of four cases in pediatric and young adult patients with a discussion of therapeutic strategies

IntroductionRelentless placoid chorioretinitis (RPC) is a rare, bilateral disease of the retinal pigment epithelium. The clinical course is prolonged and relapsing. No standard treatment has been established to date. The purpose of this case series is to report four cases of RPC in pediatric and young adult patients in which varying treatments were used, comparing them to previously published cases.MethodsA literature review was conducted to investigate currently published presentations and treatment options for RPC. A multicenter retrospective chart review was also performed on four consecutive patients. These patients were diagnosed with RPC because of new chorioretinitis lesions continuing to appear without or despite therapy for 5–36 months (2 patients), with a clinical course prolonged and relapsing, or because of the atypical location of the multiple lesions (>50) extending from the posterior pole to the equator and mid-peripheral retina (all four patients), which were not consistent with other entities like acute posterior multifocal placoid pigment epitheliopathy and serpiginous choroiditis.ResultsAll four cases of RPC received oral or IV steroids acutely, and three of these patients were transitioned to a steroid-sparing agent and biologic therapy: anti-TNF alpha or anti-IL-6. Quiescence of the chorioretinitis lesions was obtained after 7 months, 1 month, and 36 months; however, the latter had issues with treatment adherence. Mycophenolate mofetil was insufficient to control the disease in one patient, but tocilizumab and infliximab thereafter were effective after cessation of adalimumab due to side effects. Adalimumab when started the first month after the presentation was effective in controlling the disease in one patient. After the failure of interferon-alpha-2a, one patient displayed long-term control with infliximab. One patient did not require a steroid-sparing agent after oral prednisone taper as there was no evidence of progression or recurrence.ConclusionThis case series adds to the current knowledge regarding potential treatments for RPC, specifically the use of anti-TNF-alpha treatment and anti-IL-6 tocilizumab. In this case study, relapses of RPC were found among patients on mycophenolate mofetil and interferon-alpha-2a, and one case did not relapse on oral steroids without a steroid-sparing agent. Our findings suggest that adalimumab, infliximab, and tocilizumab may be useful medications to obtain quiescence of RPC

Cytotoxic NKG2C+ CD4 T cells target oligodenfrocytes in Multiple Sclerosis

The mechanisms whereby immune cells infiltrating the central nervous system in multiple sclerosis (MS) contribute to tissue injury remain to be defined. CD4 T cells are implicated as key mediators of the deleterious inflammation observed in MS. Myelin reactive CD4 T cells expressing CD56, an NK cell marker, were previously shown to be cytotoxic to human oligodendrocytes in vitro. We sought to determine whether myelin reactive CD4 T cells could also express and utilize other NK associated markers to mediate oligodendrocyte directed cytotoxicity. We observed that myelin reactive CD4 T cell lines, as well as short term PHA-activated CD4 T cells can express NKG2C, the activating receptor that interacts with HLA-E, a non-classical MHC class I molecule. These cells co-expressed CD56, had elevated levels of cytotoxic molecules FasL, granzyme B and perforin compared to their NKG2C-negative counterparts and mediated significant in vitro cytotoxicity towards human oligodendrocytes induced to express HLA-E with pro-inflammatory cytokines. A significantly elevated proportion of ex-vivo peripheral blood CD4 T cells from MS patients expressed NKG2C compared to controls. Our immunohistochemical analysis demonstrated that MS tissue sections displayed HLA-E+ oligodendrocytes and NKG2C+ CD4 T cells. Our results implicate a novel mechanism through which infiltrating CD4T cells could contribute to tissue injury in MS.La sclérose en plaques (SEP) est caractérisée par l'infiltration de cellules immunes au sein du système nerveux central (SNC). Les mécanismes par lesquels ces cellules contribuent à la formation des lésions typiques de cette pathologie restent à élucider. Les cellules T CD4 jouent un rôle important dans l'inflammation observée en SEP. Des travaux antérieurs ont démontré que des cellules T CD4 spécifiques à la myéline et exprimant le CD56, un marqueur des cellules NK, ont une activité cytotoxique in vitro dirigée contre les oligodendrocytes humains. Nous avons déterminé si les cellules T CD4 réactives à la myéline expriment et utilisent d'autres marqueurs NK impliqué dans cette cytotoxicité contre les oligodendrocytes. Nous avons observé que des lignées de cellules T CD4 spécifiques pour la myéline, ainsi que des cellules T CD4 activées par la PHA peuvent exprimer le NKG2C, le récepteur activateur qui interagit avec le HLA-E, une molécule non-classique du CMH de classe I. Les cellules T CD4 positives pour le NKG2C co-expriment le CD56, des niveaux élevés de molécules cytotoxiques tels que le FasL, le granzyme B et la perforine par rapport à leurs homologues n'exprimant pas le NKG2C. Nous avons aussi montré que ces cellules sont cytotoxiques envers des oligodendrocytes humains, qui expriment le HLA-E suite à un traitement avec des cytokines des inflammatoires. La proportion des cellules T CD4 exprimant le NKG2C est significativement plus élevée dans les échantillons de sang ex-vivo provenant de patients atteints de la SEP par rapport à ceux des témoins. Nous avons observé par immunohistochimie sur des coupes de tissus de patients atteints de la SEP la présence d'oligodendrocytes exprimant le HLA-E ainsi que des cellules T CD4 arborant le NKG2C. Nos résultats révèlent un nouveau mécanisme par lequel les cellules T CD4 pourraient contribuer directement à la formation des lésions tissulaires observées dans le SNC des patients atteints de la SEP

Vitreoretinal lymphoma

10.3390/cancers13163921Cancers1316392

Biocompatibility and Functionality of a Tissue-Engineered Living Corneal Stroma Transplanted in the Feline Eye

PURPOSE. Corneal tissue shortage has become a major concern worldwide, which has motivated the search for alternative solutions to eye bank human eyes for corneal transplantation. Minimally invasive lamellar transplantation and tissue engineering may offer new opportunities for the rehabilitation of diseased corneas. The aim of this study was to evaluate the biocompatibility and functionality of stromal lamellar grafts tissue-engineered (TE) in vitro and transplanted in vivo in the cornea of a feline model. METHODS. The corneal stromas were engineered in culture from corneal stromal cells using the self-assembly approach, without the addition of exogenous material or scaffold. Eight healthy animals underwent two intrastromal grafts in one eye and the contralateral eye was used as a control. Animals were followed with slit-lamp ophthalmic examination, corneal esthesiometry and optical coherent tomography. Confocal microscopy, immunofluorescence, histology, and transmission electron microscopy (TEM) were performed at 4 months. RESULTS. Four months after transplantation, the TE-stromal grafts were transparent, functional, and well tolerated by the eye. All grafts remained avascular, with no signs of immune rejection, despite a short course of low-dose topical steroids. Corneal sensitivity returned to preoperative level and reinnervation of the grafts was confirmed by confocal microscopy and immunofluorescence. Histology and TEM of the TE-grafts showed a lamellar stromal structure with regular collagen fibril arrangement. CONCLUSIONS. These results open the way to an entirely new therapeutic modality. Intracorneal filling using a biocompatible, transparent, and malleable TE-stroma could be the basis for multiple types of novel therapeutic options in corneal interventional surgery