Dramatic Reduction in Corneal Transplants for Keratoconus 15 Years After the Introduction of Corneal Collagen Crosslinking.

PURPOSE: The aim of this study was to investigate the effect of the implementation of corneal collagen crosslinking (CXL) on the frequency of corneal transplants among patients with keratoconus (KC) in the same region. METHODS: Before the introduction of CXL in 2007, 55 primary corneal transplants had been conducted in patients with KC (2005 and 2006) at the Department of Ophthalmology, Oslo University Hospital, Norway. We collected data from our corneal transplant registry for 2021 and 2022. The primary outcome was the number of corneal transplants performed in patients with KC. Age, sex, visual acuity (logarithm of the minimal angle of resolution), KC stage according to the Amsler-Krumeich classification system, and steepest keratometry reading (maximum keratometry, Pentacam, HR) were recorded. Furthermore, we registered the annual number of CXL treatments conducted from 2007 to 2022. RESULTS: A total of 352 corneal transplants were performed in 2021 and 2022. Among them, 11 (3.1%) were transplants for patients with KC. All included patients were male; further, 90.1% and 9.1% of the patients were graded stages 4 and 3, respectively. The mean maximum keratometry was 79.0 diopter (range 61.0-109). The mean best-corrected visual acuity (logarithm of the minimal angle of resolution) was 1.3 (range 0.2-3.0). In 2021 to 2022, 431 CXL treatments were performed. CONCLUSIONS: There was a significant decrease in the number of corneal transplants performed in patients with KC 15 years after the introduction of CXL. This indicates that the availability of CXL treatment over many years may considerably reduce the need for keratoplasties in this group of patients.

Lower risk of graft dislocation applying organ cultured corneas compared with cold short-term cultured corneas during DSAEK surgery.

BACKGROUND: To investigate factors that may affect graft dislocation after uneventful Descemet stripping endothelial keratoplasty (DSAEK), with a special focus on different donor cornea storage conditions. METHODS: All DSAEK surgeries performed during 6 years in our hospital were retrospectively investigated. Patients with previous intraocular surgeries other than cataract extraction were excluded. Donor data (age, gender, death-to-preservation time, cornea storage conditions, graft storage time, and estimated thickness of the graft) and patient information (age, gender, and indication for surgery) were noted. RESULTS: A total of 26 dislocations (6.6%) out of 394 DSAEK surgeries were found. The dislocation rate was considerably reduced between 2011 and 2016, due to more experienced surgeons. There was a significantly higher dislocation rate with the use of donor corneas stored in cold storage solution (12.7%) compared with organ culture solution (2.5%) (P < 0.001). During the study period, donor corneas stored in cold storage solution and organ culture solution were applied in 158 (40%) and 236 (60%) cases, respectively. There were no differences in recipient age and gender between patients who received corneas from the two storage systems, indicating a random distribution of grafts. In a multivariate analysis, only operation year (reduced rate over the years) and cold storage solution were statistically significantly associated with graft dislocation. CONCLUSION: This study suggests that the type of storage solution may have a decisive role in graft dislocation in DSAEK surgery.

Ten-year reinvestigation of ocular manifestations in Marfan syndrome.

IMPORTANCE: Long-term follow-up of Marfan syndrome (MFS) patients. BACKGROUND: Investigate changes in ocular features in MFS patients fulfilling the Ghent-2 criteria following a period of 10 years. DESIGN: Repeated cross-sectional study with two observations. PARTICIPANTS: Eighty-four MFS patients were investigated in 2003-2004 (baseline). Forty-four of these patients (52%) were examined after 10 years. METHODS: A comprehensive ocular examination performed at baseline and follow-up. MAIN OUTCOME MEASURES: Development or progression of ectopia lentis (EL). RESULTS: At follow-up, mean age was 50.1 ± 11.9 years (range: 30-80 years), 74% were female and 70% of the patients were diagnosed with EL compared to 66% at baseline. Two patients (3 eyes) had developed EL over the decade, representing a 13% risk. Furthermore, one eye had progressed from a subtle tilt of the lens to dislocation. We found no significant change in the axial length (P = 0.96), the corneal curvature (P = 0.64) or the spherical equivalent (P = 0.23). Best corrected visual acuity was improved at follow-up (P = 0.02). There were 7% and 33% risks for development of retinal detachment and cataract between baseline and follow-up, respectively. CONCLUSIONS AND RELEVANCE: Our study indicates that even though EL typically occurs at an early stage in most MFS patients, there is still a risk of developing EL in adulthood. The risk of developing vision-threatening complications such as retinal detachment and cataract was much higher than in the normal population, but even so, the visual potential of the MFS patients was relatively good.

Does Corneal Collagen Cross-linking Reduce the Need for Keratoplasties in Patients With Keratoconus?

PURPOSE: To investigate whether the introduction of corneal collagen cross-linking (CXL) influences the frequency of keratoplasties in patients with keratoconus. METHODS: Data were obtained from a cohort of patients from our corneal transplant registry. Two different periods were compared, 2005 to 2006 (period 1) and 2013 to 2014 (period 2). Patients during period 1 had surgery before the introduction of CXL treatment, and patients in period 2 had surgery after this treatment was well established in our department. Age and gender were registered, and the Amsler-Krumeich classification system was applied to grade the degree of keratoconus. RESULTS: The total number of keratoplasties performed during period 1 was 137, and keratoconus was the cause of surgery in 55 eyes (55 patients). The corresponding numbers in period 2 were 231 and 26 eyes (26 patients), respectively. The difference in the number of keratoplasties for keratoconus in both periods was statistically significant (P = 0.003). There were no significant differences in the distributions of age and gender between both periods. In period 1, 63.6% of the eyes were graded as stage 4 in the Amsler-Krumeich classification, compared with 96.2% in period 2 (P = 0.001). CONCLUSIONS: The frequency of keratoplasty for keratoconus has been more than halved in our department over the last decade. There is reason to believe that this reduction is for a great part caused by the introduction of CXL treatment.

The role of postoperative positioning after DSAEK in preventing graft dislocation.

PURPOSE: The aim of the study was to evaluate the importance of immediate postoperative supine patient positioning after Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: Forty eyes from 40 patients who underwent DSAEK were randomized into two groups: 20 patients sat in a chair for 2 hr postoperatively (group 1), and 20 patients were placed in a supine position (group 2) for the same time interval. At the end of surgery, the anterior chamber was fully filled with air, aiming at an intraocular pressure (IOP) of approximately 20 mmHg. The dislocation rate in the two groups was registered. IOP was measured 2 hr postoperatively and compared with endothelial cell loss at 6 months. RESULTS: There was no statistically significant difference in the dislocation rate between the two groups (p = 0.548): two patients (10%) in group 1 and one patient (5%) in group 2. Endothelial cell loss at 6 months was 29.6% and 29.7% in group 1 and 2, respectively. There was no correlation between the IOP 2 hr after surgery and endothelial cell loss at 6 months (p = 0.741). CONCLUSION: Supine positioning does not seem to be of crucial importance in avoiding graft dislocation in DSAEK when the anterior chamber is fully filled with air for 2 hr postoperatively.

Posterior capsular opacification in patients with pseudoexfoliation syndrome: a long-term perspective.

PURPOSE: To compare posterior capsular opacification in patients with and without pseudoexfoliation syndrome 6-7 years following surgery. METHODS: Forty-four eyes of 44 patients with pseudoexfoliation syndrome who underwent cataract surgery with phacoemulsification in 2001 and 2002 were available for follow-up in 2008. These patients were compared to 86 age- and gender-matched patients (86 eyes) without pseudoexfoliation syndrome who had surgery during the same time period. Posterior capsule opacification was assessed using digital retroillumination photography. The images were analysed with a software program (POCOman) to determine the extent and severity of the capsular opacification. RESULTS: Percentage and severity of posterior capsular opacification within the central 4.0 and 1.3 mm of the optical zone were compared in eyes with and without pseudoexfoliation syndrome. Neither of these results were statistically significant. Before the re-examination in 2008, neodymium:yttrium-aluminium-garnet laser posterior capsulotomy had been conducted in 16% (n = 7) of eyes with pseudoexfoliation syndrome, as well as in 16% (n = 14) of eyes without pseudoexfoliation syndrome. CONCLUSION: Our study indicates that, with phacoemulsification, development of long-term posterior capsular opacification is not increased in patients with pseudoexfoliation syndrome after uncomplicated cataract surgery.

Cytokine secretion depends on Galalpha(1,3)Gal expression in a pig-to-human whole blood model.

Transplants from alpha1,3-galactosyltransferase (Gal) gene-knockout pigs to nonhuman primates are largely protected from hyperacute but not acute humoral xenograft rejection. The present study investigates the role of Gal in cytokine responses using a novel pig-to-human whole blood in vitro model, developed for species-specific analysis of porcine and human cytokines. Porcine (n = 7) and human (n = 27) cytokines were measured using ELISA or multiplex technology, respectively. Porcine aortic endothelial cells from control (Gal(+/+)) and Gal-deficient (Gal(-/-)) pigs were incubated with human lepirudin anticoagulated whole blood from healthy donors. E-selectin expression was measured by flow cytometry. The C3 inhibitor compstatin and a C5aR antagonist were used to study the role of complement. Cytokine species specificity was documented, enabling detection of 2 of 7 porcine cytokines and 13 of 27 human cytokines in one single sample. Gal(+/+) porcine aortic endothelial cells incubated with human whole blood showed a marked complement C5b-9 dependent up-regulation of E-selectin and secretion of porcine IL-6 and IL-8. In contrast, Gal(-/-) cells responded with E-selectin and cytokine expression which was so weak that the role of complement could not be determined. Human IL-6, IL-8, IFN-gamma, MIP-1alpha, MIP-1beta, eotaxin, and RANTES were detected in the Gal(+/+) system, but virtually no responses were seen in the Gal(-/-) system (p = 0.03). The increase in human cytokine release was largely complement dependent and, in contrast to the porcine response, mediated through C5a. Species-specific analysis of cytokine release revealed a marked, complement-dependent response when Gal(+/+) pig cells were incubated with human whole blood, compared with Gal(-/-) cells which induced virtually no cytokine release.

Characterization of natural human anti-non-gal antibodies and their effect on activation of porcine gal-deficient endothelial cells.

BACKGROUND: The generation of Galalpha1-3Gal (Gal) transferase deficient pigs has increased the interest in non-Gal antigens potentially representing important targets for xenoreactive antibody binding leading to xenograft rejection. The present study addressed the levels and immunoglobulin isotypes of preformed human anti-non-Gal antibodies and their potential to activate porcine endothelial cells. METHODS: Porcine endothelial cells lacking the Gal epitope (Gal-/-) were used to measure immunoglobulin (Ig) M and IgG subclass anti-non-Gal antibodies, using sera from 80 blood donors and pooled human AB serum. Antibodies specific for the non-Gal Hanganutziu-Deicher (HD) xenoantigen were measured by enzyme-linked immunosorbent assay. Activation of Gal-/- and Gal+/+ endothelial cells by human serum was measured, in the presence or absence of complement inhibitors, by E-selectin cell-surface expression using flow cytometry. RESULTS: Anti-non-Gal antibody levels varied considerably among individual sera and comprised approximately 10% of total anti-porcine antibodies without sex or age differences. Among the IgG subclasses only IgG1 and IgG2 were detected. Human serum-induced E-selectin expression on Gal-/- cells was less than 20% compared with Gal+/+ cells, correlated with anti-HD IgM and IgG antibody levels (P=0.027 and 0.032, respectively), and was largely complement-independent in accordance with the lack of IgG3 anti-non-Gal antibodies. In contrast, E-selectin upregulation on Gal+/+ cells was reduced in complement blocking experiments. CONCLUSION: Preformed anti-non-Gal antibodies, in particular anti-HD antibodies, were present in all human sera samples, activated porcine endothelial cells, and may therefore play a role in xenograft rejection using organs from GalT-/- pigs.

Human complement-activating immunoglobulin (Ig)G3 antibodies are essential for porcine endothelial cell activation.

BACKGROUND: Complement-activating naturally occurring anti-porcine endothelial cell antibodies (Abs) are responsible for hyperacute rejection in porcine-to-primate transplantation, whereas the role of complement in acute vascular rejection, characterized by type II endothelial cell activation, is less well understood. We previously demonstrated a correlation between porcine type II endothelial cell activation, as detected by E-selectin expression, and human immunoglobulin (Ig)G3 anti-Gal alpha1-3Gal (Gal) Abs, which was not seen for IgG1, IgG2 or IgG4. The present study was undertaken to investigate whether there is a causal relationship between human anti-porcine IgG3 Abs and porcine endothelial cell activation. METHODS: IgG3 was isolated employing a Protein A column to 98.3% purity. Porcine endothelial cells were incubated with isolated human IgG3 or the combination of IgG1, IgG2 and IgG4. E-selectin expression and complement activation were investigated by flow cytometry and Western blotting, respectively. RESULTS: Purified IgG3, in contrast to the other IgG subclasses, induced a substantial increase in E-selectin expression. This activation was accompanied by complement activation as detected by C3 cleavage, and was abolished by heat inactivation or by adding the complement inhibitor FUT-175. Depletion of anti-Gal Abs reduced E-selectin expression by 60%, consistent with the presence of complement-activating anti-porcine non-Gal Abs of the IgG3 subclass. CONCLUSIONS: Collectively, these data strengthen the hypothesis that human anti-porcine endothelial cell Abs of the IgG3 subclass are essential for endothelial cell activation in porcine-to-human species grafts and demonstrate such activation to be partly independent of Gal epitopes.

Human serum-induced porcine endothelial cell E-selectin expression is associated with IgG3 and IgM anti-Gal antibodies.

Naturally occurring anti-Galalpha1-3Gal (anti-Gal) antibodies and complement induce hyperacute rejection (HAR) of porcine organs transplanted to primates. If the hyperacute reaction is prevented, an acute vascular rejection (AVR) occurs within hours to few days. Antibodies are important for the development of AVR, whereas the role of complement is still not clarified. AVR is characterized by protein synthesis-dependent endothelial cell (EC) activation. In the present study we investigated the relation between EC activation as measured by E-selectin expression, and the concentrations of anti-Gal antibodies of IgM, IgG and IgG subclasses in sera from 80 healthy blood donors selected on the basis of sex and age. There was a significant correlation between E-selectin expression and the concentration of IgG3 anti-Gal (r=0.39; P=0.019), which was not seen for the other IgG subclasses or for total IgG anti-Gal. A modest, but significant correlation was found between the concentration of IgM anti-Gal and E-selectin expression (r=0.38; P=0.040), but not between IgM and IgG3 anti-Gal. There was a large interindividual variation in anti-Gal antibodies, 50-fold for IgM and 70-fold for IgG. Females had significantly higher concentrations of IgM anti-Gal than males (P=0.0006), which was explained by a substantial increase in IgM anti-Gal concentration in younger women. The concentration of IgG anti-Gal and the degree of E-selectin expression did not differ between sex or age groups. In conclusion, the close correlation between anti-Gal antibodies of the potent complement activating IgG3 subclass and porcine EC activation, may imply that these antibodies play a role in EC activation characteristic of AVR.