Purpose: To analyze the age dependence of the longitudinal modulus of the crystalline lens in vivo using Brillouin scattering data in healthy subjects. Methods: Brillouin scans were performed along the crystalline lens in 56 eyes from 30 healthy subjects aged from 19 to 63 years. Longitudinal elastic modulus was acquired along the sagittal axis of the lens with a transverse and axial resolution of 4 and 60 μm, respectively. The relative lens stiffness was computed, and correlations with age were analyzed. Results: Brillouin axial profiles revealed nonuniform longitudinal modulus within the lens, increasing from a softer periphery toward a stiffer central plateau at all ages. The longitudinal modulus at the central plateau showed no age dependence in a range of 19 to 45 years and a slight decrease with age from 45 to 63 years. A significant intersubject variability was observed in an age-matched analysis. Importantly, the extent of the central stiff plateau region increased steadily over age from 19 to 63 years. The slope of change in Brillouin modulus in the peripheral regions were nearly age-invariant. Conclusions: The adult human lens showed no measurable age-related increase in the peak longitudinal modulus. The expansion of the stiff central region of the lens is likely to be the major contributing factor to age-related lens stiffening. Brillouin microscopy may be useful in characterizing the crystalline lens for the optimization of surgical or pharmacological treatments aimed at restoring accommodative power.

Human corneal endothelial cells are derived from neural crest and because of postmitotic arrest lack competence to repair cell loss from trauma, aging, and degenerative disorders such as Fuchs endothelial corneal dystrophy (FECD). Herein, we identified a rapidly proliferating subpopulation of cells from the corneal endothelium of adult normal and FECD donors that exhibited features of neural crest-derived progenitor (NCDP) cells by showing absence of senescence with passaging, propensity to form spheres, and increased colony forming efficacy compared with the primary cells. The collective expression of stem cell-related genes SOX2, OCT4, LGR5, TP63 (p63), as well as neural crest marker genes PSIP1 (p75(NTR)), PAX3, SOX9, AP2B1 (AP-2β), and NES, generated a phenotypic footprint of endothelial NCDPs. NCDPs displayed multipotency by differentiating into microtubule-associated protein 2, β-III tubulin, and glial fibrillary acidic protein positive neurons and into p75(NTR)-positive human corneal endothelial cells that exhibited transendothelial resistance of functional endothelium. In conclusion, we found that mitotically incompetent ocular tissue cells contain adult NCDPs that exhibit a profile of transcription factors regulating multipotency and neural crest progenitor characteristics. Identification of normal NCDPs in FECD-affected endothelium holds promise for potential autologous cell therapies.

Limbal stem cell deficiency is predominantly caused by severe eye burns resulting in a decreased or a complete ablation of the regenerative potential of these stem cells. The inability to reconstruct the corneal epithelium further leads conjunctivalization of the gimbal-epithelial barrier. These abnormalities collectively result in the progressive opacification of the cornea responsible for blindness that is driven by chronic corneal ulceration and neovascularization. The underlying pathology of the cornea affects the homeostasis of the neighboring conjunctiva, eyelids, and tear film. Therefore, the ocular reconstruction to treat limbal stem cell deficiency is quite prolonged and involves a continued treatment plan. The management of limbal stem cell deficiency has undergone a multitude of changes over the past several decades. The understanding of limbal anatomy and physiology, as well as therapeutic advances in the stem cell field have propelled the development of new treatments offering new hope to severely disabled patients. Cultivated limbal epithelial and oral mucosal epithelial transplantations are therefore viable alternatives that could be utilized for the treatment of limbal stem cell deficiency.

Endothelial keratoplasty (EK) has replaced penetrating keratoplasty (PKP) as the preferred surgical therapy for corneal endothelial dysfunction. However, recent nationwide corneal graft registry data showed few advantages to EK relative to PKP with respect to graft survival and visual outcomes. This article compares the published outcomes and complications of EK to those of PKP. EK demonstrates superior spectacle corrected visual outcomes, fast recovery, less graft rejection, and higher patient satisfaction, particularly in studies performed by high-volume surgeons/centers. Endothelial cell loss in EK, while higher at early time points, was equivalent or superior at five-years' follow-up and graft survival was equivalent to or superior to PKP in these centers/studies. Continued standardization and simplification of EK procedures may allow surgeons who perform a lower volume of EK to achieve results that mirror those of high-volume centers/surgeons and close the potential gap in outcomes demonstrated in the registry data.

Transparency of the cornea is indispensable for optimal vision. Ocular trauma is a leading cause of corneal opacity, leading to 25 million cases of blindness annually. Recently, mesenchymal stem cells (MSCs) have gained prominence due to their inflammation-suppressing and tissue repair functions. Here, we investigate the potential of MSCs to restore corneal transparency following ocular injury. Using an in vivo mouse model of ocular injury, we report that MSCs have the capacity to restore corneal transparency by secreting high levels of hepatocyte growth factor (HGF). Interestingly, our data also show that HGF alone can restore corneal transparency, an observation that has translational implications for the development of HGF-based therapy.

PURPOSE: To evaluate the feasibility of Descemet stripping endothelial keratoplasty using grafts preloaded by an eye bank in a commercially available insertion device. METHODS: In this retrospective case series, a series of 35 eyes in 34 consecutive patients who underwent Descemet stripping endothelial keratoplasty for Fuchs endothelial dystrophy or previously failed full-thickness grafts at a single tertiary care center from March 2013 to March 2014 was included. The donor tissue had undergone pre-lamellar dissection, trephination, and loading into EndoGlide Ultrathin inserters at the Lions Eye Institute for Transplant and Research (Tampa, FL) and was shipped overnight in Optisol GS to the surgeon (K.C.). Surgery was performed within 24 hours from tissue preparation and loading by the eye bank. Donor and recipient characteristics, endothelial cell density (ECD), best-corrected visual acuity, and central corneal thickness were recorded. The main outcome measures were intraoperative and postoperative complications and ECD loss at 3, 6, and 12 months. RESULTS: One primary graft failure (2.8%), 2 rebubblings (5.7%), and 1 graft rejection (2.8%) occurred. Mean preoperative donor ECD was 2821 ± 199 cells/mm. Six months postoperatively, the mean endothelial cell loss was 25.3% ± 17.2% (n = 32), which remained stable at 1 year (31.5% ± 17.9%, n = 32). Mean best-corrected visual acuity improved from 20/100 preoperatively to 20/25 at a mean follow-up of 1 year (n = 32). Mean central corneal thickness was reduced from 711 ± 110 μm to 638 ± 66 μm at the last follow-up visit. CONCLUSIONS: Donor graft tissue preloaded by an eye bank can be used successfully for endothelial keratoplasty. Preloading reduces intraoperative tissue manipulation.

Mucins are a group of highly glycosylated glycoproteins responsible for the protection of wet-surfaced epithelia. Recent data indicate that transmembrane mucins differ in their contribution to the protective function of the ocular surface, with MUC16 being the most effective barrier on the apical surface glycocalyx. Here, we investigated the role of the mucoprotective drug rebamipide in the regulation of transmembrane mucin biosynthesis using stratified cultures of human corneal and conjunctival epithelial cells. We find that the addition of rebamipide to corneal, but not conjunctival, epithelial cells increased MUC16 protein biosynthesis. Rebamipide did not affect the levels of MUC1, 4 and 20 compared to control. In these experiments, rebamipide had no effect on the expression levels of Notch intracellular domains, suggesting that the rebamipide-induced increase in MUC16 biosynthesis in differentiated corneal cultures is not regulated by Notch signaling. Overall these findings indicate that rebamipide induces the differential upregulation of MUC16 in stratified cultures of human corneal epithelial cells, which may have implications to the proper restoration of barrier function in ocular surface disease.

Goblet cells within the conjunctival epithelium are specialized cells that secrete mucins onto the surface of the eye. Recent research has demonstrated new characteristics of the cells, including factors influencing their differentiation, their gene products and their functions at the ocular surface. The following review summarizes the newly discovered aspects of the role of Spdef, a member of the Ets transcription factor family in conjunctival goblet cell differentiation, the newly discovered goblet cell products including claudin2, the Wnt inhibitor Frzb, and the transmembrane mucin Muc16. The current concepts of conjunctival goblet cell function, including debris removal and immune surveillance are reviewed, as are changes in the goblet cell population in ocular surface diseases. Major remaining questions regarding conjunctival cell biology are discussed.

Dendritic cells (DCs) are antigen-presenting cells that normally play a critical role in stimulating T-cell-dependent immune responses. However, tolerogenic DCs (CD11cMHC-IICD80CD86) induce immune tolerance by stimulating regulatory T cells (Tregs: CD4CD25Foxp3). Although tolerogenic DCs are used to treat autoimmune diseases and to prevent transplantation rejection, the mechanisms by which they regulate alloimmunity are poorly understood. Here, we review our previous studies aiming to elucidate the mechanisms involved in immune rejection of corneal allografts using a corneal transplant model. We found that donor-derived tolerogenic DCs significantly prolonged corneal allograft survival by suppressing indirect allosensitization. We also reported the precise distribution of intraepithelial corneal DCs, termed Langerhans cells (LCs: CD11cLangerinMHC-II) in the cornea, which we maintain play a critical role in regulating corneal immunity. By confocal microscopy, we constructed 3-dimensional images of corneal LCs, which demonstrated that their cell bodies are present in the basal cell layer of the corneal epithelium. Furthermore, LC dendrites extend toward the ocular surface, but do not connect to epithelial tight junctions, indicating that they cannot directly interact with ocular surface antigens. We confirm the potential of DC therapy for corneal graft rejection and report the function of intraepithelial DCs (LCs) in the normal cornea.

Accumulating evidence shows that IL-17 is critically involved in diverse autoimmune diseases. However, its effect on the induction and progression of the humoral immune response is not fully understood. Using a preclinical model of IL-17-mediated dry eye disease, we demonstrate that upon encountering both the BCR and a secondary T cell signal, IL-17 can enhance B cell proliferation and germinal center formation in dry eye disease mice, suggesting that a stable Ag-dependent T-B cell interaction is required. Additionally, IL-17 also promotes the differentiation of B cells into isotype-switched B cells and plasma cells. Furthermore, we show that Th17 cells are more effective than Th1 cells to provide B cell help. Reduced B cell response correlates with significant reduction in clinical disease after in vivo IL-17A neutralization. In conclusion, our findings demonstrate a new role of IL-17 in promoting autoimmunity in part through directly enhancing B cell proliferation, differentiation, and plasma cell generation.

In a fibroblast colony model of corneal stromal development, we asked how physiological tension influences the patterning dynamics of fibroblasts and the orientation of deposited extracellular matrix (ECM). Using long-term live-cell microscopy, enabled by an optically accessible mechanobioreactor, a primary human corneal fibroblast colony was cultured on three types of substrates: a mechanically biased, loaded, dense, disorganized collagen substrate (LDDCS), a glass coverslip, and an unloaded, dense, disorganized collagen substrate (UDDCS). On LDDCS, fibroblast orientation and migration along a preferred angle developed early, cell orientation was correlated over long distances, and the colony pattern was stable. On glass, fibroblast orientation was poorly correlated, developed more slowly, and colony patterns were metastable. On UDDCS, cell orientation was correlated over shorter distances compared with LDDCS specimens. On all substrates, the ECM pattern reflected the cell pattern. In summary, mechanically biasing the collagen substrate altered the early migration behavior of individual cells, leading to stable emergent cell patterning, which set the template for newly synthesized ECM.

: In humans, the lacrimal gland (LG) is the primary contributor to the aqueous layer of the tear film. Production of tears in insufficient quantity or of inadequate quality may lead to aqueous-deficiency dry eye (ADDE). Currently there is no cure for ADDE. The development of strategies to reliably isolate LG stem/progenitor cells from the LG tissue brings great promise for the design of cell replacement therapies for patients with ADDE. We analyzed the therapeutic potential of epithelial progenitor cells (EPCPs) isolated from adult wild-type mouse LGs by transplanting them into the LGs of TSP-1(-/-) mice, which represent a novel mouse model for ADDE. TSP-1(-/-) mice are normal at birth but progressively develop a chronic form of ocular surface disease, characterized by deterioration, inflammation, and secretory dysfunction of the lacrimal gland. Our study shows that, among c-kit-positive epithelial cell adhesion molecule (EpCAM(+)) populations sorted from mouse LGs, the c-kit(+)dim/EpCAM(+)/Sca1(-)/CD34(-)/CD45(-) cells have the hallmarks of an epithelial cell progenitor population. Isolated EPCPs express pluripotency factors and markers of the epithelial cell lineage Runx1 and EpCAM, and they form acini and ducts when grown in reaggregated three-dimensional cultures. Moreover, when transplanted into injured or "diseased" LGs, they engraft into acinar and ductal compartments. EPCP-injected TSP-1(-/-) LGs showed reduction of cell infiltration, differentiation of the donor EPCPs within secretory acini, and substantial improvement in LG structural integrity and function. This study provides the first evidence for the effective use of adult EPCP cell transplantation to rescue LG dysfunction in a model system. SIGNIFICANCE: In humans, the lacrimal gland is the primary contributor to the aqueous layer of the tear film. Damage or inflammation of the lacrimal gland may lead to severe aqueous-deficiency dry eye and corneal disease. Endogenous lacrimal gland epithelial cell progenitors (EPCPs) injected into the gland of mouse model of human Sjögren's syndrome TSP-1(-/-) mice resulted in long-term engraftment and markedly improved structure and function of "diseased" lacrimal gland. This study demonstrates, for the first time, that EPCPs can mediate functional recovery of the lacrimal gland in a Sjögren's syndrome mouse model. These data establish proof of concept that endogenous stem/progenitor cell transplantation may be used to treat human lacrimal gland chronic inflammation.

PURPOSE: To compare postoperative ocular surface integrity and innervation between small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS: The Cochrane Central Register of Controlled Trials, PubMED, and EMBASE were searched for prospective comparative studies. Trials meeting the selection criteria were quality appraised, and the data were extracted by 2 independent authors. The weighted mean differences (WMDs) and 95% confidence intervals (CIs) were used to compare dry eye examinations and corneal subbasal nerve density (SMILE-FS-LASIK). RESULTS: The study covered 5 trials. No significant difference was found in the Schirmer test score between both groups (WMD = -1.91 and 0.27; 95% CI, -5.02 to 1.20 and -0.99 to 1.54; P = 0.23 and 0.67 at 1- and 6-month follow-ups, respectively). Tear breakup time in the SMILE group significantly exceeded that in the FS-LASIK group (WMD = 0.65 and 1.14; 95% CI, 0.20-1.10 and 0.18-2.10; P = 0.004 and 0.02, at 1- and 6-month follow-ups, respectively). Ocular surface disease index scores were significantly better in the SMILE group 6 months postoperatively (WMD = -10.12, 95% CI, -16.07 to -4.18, P = 0.0008). No significant difference was found in tear osmolarity between both groups (WMD = -5.19 and -6.37; 95% CI, -17.15 to 6.76 and -22.74 to 10.00; P = 0.39 and 0.45 at 1- and 6-month follow-ups, respectively). Higher corneal sensitivity was observed in the SMILE group 1 and 6 months postoperatively (WMD = 11.35 and 3.49; 95% CI, 7.29-15.40 and 1.76-5.21; P < 0.00001 and <0.0001, at 1- and 6-month follow-ups, respectively). Corneal subbasal nerve density was also significantly higher in SMILE-treated eyes than it was in FS-LASIK-treated eyes 1 month postoperatively (WMD = 4.72, 95% CI, 1.10-8.34, P = 0.01). CONCLUSIONS: According to this meta-analysis, the SMILE procedure has fewer negative impacts on the ocular surface and corneal innervation than does FS-LASIK. Furthermore, SMILE shows superiority over FS-LASIK by a exhibiting a lower risk of postoperative dry eye.

PURPOSE: To report the long-term visual outcomes and complications after Boston keratoprosthesis type II implantation in the largest single-center case series with the longest average follow-up. DESIGN: Retrospective review of consecutive clinical case series. PARTICIPANTS: Between January 1992 and April 2015 at the Massachusetts Eye and Ear Infirmary, 48 eyes of 44 patients had keratoprosthesis type II implanted by 2 surgeons (C.H.D. and J.C.). METHODS: For each eye, data were collected and analyzed on the preoperative characteristics, intraoperative procedures, and postoperative course. MAIN OUTCOME MEASURES: Visual acuity outcomes, postoperative complications, and device retention. RESULTS: The most common indications for surgery were Stevens-Johnson syndrome in 41.7% (20 of 48 eyes) and mucous membrane pemphigoid in 41.7% (20 of 48 eyes). Mean follow-up duration was 70.2 months (standard deviation, 61.8 months; median, 52 months; range, 6 months to 19.8 years). Almost all patients (95.8%, 46 of 48 eyes) had a preoperative visual acuity of 20/200 or worse. Postoperative visual acuity improved to 20/200 or better in 37.5% (18 of 48 eyes) and to 20/100 or better in 33.3% (16 of 48 eyes) at the last follow-up visit. The most common postoperative complication was retroprosthetic membrane formation in over half (60.4%, 29 of 48 eyes). The most pressing postoperative complication was glaucoma onset or progression in about a third. Preexisting glaucoma was present in 72.9% (35 of 48 eyes). Glaucoma progressed in 27.1% (13 of 48 eyes) and was newly diagnosed in 8.3% (4 of 48 eyes) after surgery. Other postoperative complications were tarsorrhaphy revision in 52.1% (25 of 48 eyes), retinal detachment in 18.8% (9 of 48 eyes), infectious endophthalmitis in 6.3% (3 of 48 eyes), and choroidal detachment or hemorrhage in 8.3% (4 of 48 eyes). Half of eyes retained their initial keratoprosthesis at the last follow-up (50.0%, 24 of 48 eyes). CONCLUSIONS: The Boston keratoprosthesis type II is a viable option to salvage vision in patients with poor prognosis for other corneal procedures. Retroprosthetic membranes, keratoprosthesis retention, and glaucoma are major challenges in the postoperative period; however, the keratoprosthesis can still provide improved vision in a select group of patients.

PURPOSE OF REVIEW: Recent advances and outcomes data in the management of Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) demonstrate the need for a universal standard of care for patients admitted with the disease. RECENT FINDINGS: Amniotic membrane transplantation, aggressive topical corticosteroids, and lubrication in the acute stage are necessary to prevent or mitigate long-term ocular sequelae. If chronic ocular disease does occur, several interventions can be employed to prevent progressive vision loss and discomfort. The earliest interventions are the ones most likely to prevent chronic complications. SUMMARY: The literature overwhelmingly describes acute intervention for ocular involvement in SJS/TEN as improving long-term outcomes. All patients admitted for SJS/TEN or suspicion of SJS/TEN should be evaluated and then closely followed by ophthalmologists. As the disease progresses, the interventions needed for visual rehabilitation become more invasive and higher risk.

PURPOSE: Keratoconus (KC) is a corneal ectasia whose pathophysiology is still mostly unknown. We investigated whether thyroid gland dysfunction (TGD) is associated with the development of KC. METHODS: We first conducted an epidemiological study, examining the prevalence of TGD among patients with KC. Then, we compared tear thyroxine (T4) in TGD and immunohistochemical staining of its receptors (T4Rs) between patients with KC and controls. The significance of T4 for corneal metabolism was studied in organotypic tissue cultures from monkey corneas. RESULTS: We found that TGD prevalence among patients with KC is 13.6%, which is higher than its prevalence in the general population (about 2%). Tear T4 was higher in KC, and keratocyte T4Rs were elevated in KC compared with controls. Furthermore, core proteins such as collagen and cytokeratins were equally altered both in KC and in the cultured corneas substituted with T4. CONCLUSIONS: Our data implicate a crucial role of T4 in KC pathophysiology, which is most likely mediated by T4Rs.

Recent clinical research has highlighted important links between a number of diseases and the tortuosity of curvilinear anatomical structures like corneal nerve fibres, suggesting that tortuosity changes might detect early stages of specific conditions. Currently, clinical studies are mainly based on subjective, visual assessment, with limited repeatability and inter-observer agreement. To address these problems, we propose a fully automated framework for image-level tortuosity estimation, consisting of a hybrid segmentation method and a highly adaptable, definition-free tortuosity estimation algorithm. The former combines an appearance model, based on a Scale and Curvature-Invariant Ridge Detector (SCIRD), with a context model, including multi-range learned context filters. The latter is based on a novel tortuosity estimation paradigm in which discriminative, multi-scale features can be automatically learned for specific anatomical objects and diseases. Experimental results on 140 in vivo confocal microscopy images of corneal nerve fibres from healthy and unhealthy subjects demonstrate the excellent performance of our method compared to state-of-the-art approaches and ground truth annotations from 3 expert observers.

PURPOSE: Corneal neuropathy is a recently described disease process that is not well understood and is likely underdiagnosed as a result. This is the first reported case of an acquired corneal neuropathy associated with malposition of an Ex-PRESS shunt. METHODS: A single case report. RESULTS: We report the case of a 50-year-old man with a history of multiple procedures for glaucoma who subsequently developed photoallodynia and corneal neuropathy in association with malposition of an Ex-PRESS shunt in the peripheral cornea. Laser confocal microscopy (HRT3/RCM) of the cornea showed the presence of neuromas, decreased nerve density, and a significant increase of dendritiform immune cells consistent with our diagnosis. Initial treatment with steroid pulse therapy did not result in decreased inflammation or symptomatic improvement leading to surgical explantation of the shunt. One month after surgery, there was noticeable improvement in the patient's pain and photoallodynia (approximately 40%) as well as the abnormalities seen on confocal microscopy. CONCLUSIONS: We hypothesize that poor Ex-PRESS shunt positioning can act as a nidus for corneal inflammation, resulting in corneal neuropathy and lowering of the nociception threshold.

PURPOSE: Although it has been known that patients' perspectives on their disease can significantly affect their level of functional disability as well as disease outcome, limited data are available on patients' perceptions of their dry eye disease (DED). The aim of this questionnaire-based study was to evaluate patients' perspectives on their DED. METHODS: This cross-sectional study included 91 patients with DED. In addition to clinical evaluation, all patients completed a questionnaire to evaluate their perspectives on their DED. This included their satisfaction with understanding DED, their opinion on the easiness of following doctors' advice, their opinion on the effectiveness of the treatment, their satisfaction with the eye care, and their general outlook on DED. RESULTS: This study included 75 (82%) women and 16 men (18%) with a mean age of 57 ± 14 years who had been treated for DED for 5.2 ± 5.4 years. 93% of the patients were satisfied with their understanding of DED, and 76% found it easy to follow their doctors' advice for DED management. Furthermore, 95% thought that the DED treatment had been helpful and 95% were satisfied with their eye care for DED. Forty-eight percent expressed optimism regarding the long-term prospects of their DED. CONCLUSIONS: Although the majority of DED patients have positive perspectives on their disease, close to half report a lack of optimism regarding the long-term outlook for their condition.

PURPOSE: To report the ocular manifestations of phospholipase-Cγ2-associated antibody deficiency and immune dysregulation (PLAID). METHODS: Case report and literature review. RESULTS: A 21-year-old woman diagnosed with PLAID was referred for evaluation of repeated episodes of ocular inflammation resulting in bilateral peripheral corneal pannus with episcleritis and corneal scarring accompanied by systemic manifestations including epidermolysis bullosa and interstitial lung disease. Systemic immunosuppression with corticosteroids and interleukin-1 (IL-1) receptor antagonist (anakinra) was supplemented with topical anakinra to avoid systemic side effects, which resulted in partial improvement of the ocular symptoms. Oral prednisone was restarted to treat active lesions during bouts of inflammation. CONCLUSIONS: Ocular PLAID is a bilateral chronic or recurrent inflammatory disease of the ocular surface leading to severe and early cicatricial ocular surface and corneal involvement because of high IL-1 production. Management of PLAID may require both topical and systemic immunomodulatory treatments, potentially including targeted local anti-IL-1 therapy.

BACKGROUND: Corneal neovascularization increases the risk of T cell-mediated allograft rejection. Here, we investigate whether T cells promote angiogenesis in transplantation. METHODS: Conventional effector T cells were collected from draining lymph nodes of allogeneic or syngeneic corneal transplanted BALB/c mice. T cells were either cocultured with vascular endothelial cells (VECs) to assess VEC proliferation or used in a mixed lymphocyte reaction assay. Messenger RNA (mRNA) expression of vascular endothelial growth factor (VEGF)-A, -C, and VEGF receptor 2 (VEGF-R2) in VECs was assessed by real-time PCR. VEGF-A protein expression was determined by enzyme-linked immunosorbent assay. Flow cytometry was used to analyze VEGF-R2 expression in corneal CD31 cells, and VEGF-A and IFNγ expression in corneal CD4 T cells. RESULTS: Allogeneic T cells from high-risk (HR) grafted mice induced more VEC proliferation than those from syngeneic transplant recipients (P = 0.03). Vascular endothelial growth factor-A mRNA and protein expression were higher in T cells from draining lymph nodes (P = 0.03 and P = 0.04, respectively) and cornea (protein; P = 0.04) of HR compared with low-risk (LR) grafted hosts. Vascular endothelial growth factor-A, VEGF-C, and VEGF-R2 mRNA expression were increased in VECs when cocultured with T cells from HR transplants compared with LR transplants and naive mice. In addition, IFNγ blockade in T cell/VEC coculture increased VEC proliferation and VEGF-A protein expression, whereas blocking VEGF-A significantly reduced VEC proliferation (P = 0.04). CONCLUSIONS: Allogeneic T cells from corneal transplant hosts promote VEC proliferation, probably via VEGF-A signaling, whereas IFNγ shows an antiangiogenic effect. Our data suggest that T cells are critical mediators of angiogenesis in transplantation.

PURPOSE: Purinergic receptors play a key role in the function of the lacrimal gland (LG) as P1 purinergic receptors A1, A2A, and A2B, P2X1-7 receptors, and many of the P2Y receptors are expressed. METHODS: This review examines the current knowledge of purinergic receptors in the LG as well as the signaling pathways activated by these receptors. RESULTS: These receptors are expressed on the acinar, ductal, and myoepithelial cells. Considerable crosstalk exists between the pathways activated by P2X7 receptors with those activated by M3 muscarinic or α1D adrenergic receptors. The mechanism of the crosstalk between P2X7 and M3 muscarinic receptors differs from that of the crosstalk between P2X7 and α1D adrenergic receptors. CONCLUSIONS: Understanding purinergic receptors and how they modulate protein secretion could play a key role in normal and pathological responses of the LG.