Triamcinolone acetonide modulates permeability and intercellular adhesion molecule-1 (ICAM-1) expression of the ECV304 cell line: implications for macular degeneration

Transendothelial electrical resistance of bovine retinal capillary endothelial cells is influenced by cell growth patterns: an ultrastructural study

The purpose of this study was to describe the ultrastructural features of an in vitro capillary endothelial cell model of blood-retinal barrier permeability and to relate morphological features with transendothelial electrical resistance. The electrical resistance of endothelial cell monocultures on small and large pore size polycarbonate Transwell filters was measured and compared with cocultures of endothelial cells and Müller cells. There was a wide variation in electrical resistance measurements with many preparations not achieving a functional barrier. The ultrastructural features associated with barrier function in vitro were studied by comparing cultures that exhibited a 'tight' or 'leaky' barrier when measured immediately prior to processing for electron microscopy. Preparations with low transendothelial electrical resistance were associated with irregular cell growth when studied morphologically. It was concluded that parallel light and electron microscopic studies are important for validation of in vitro models of vascular endothelial permeability.

Combined photodynamic therapy with verteporfin and intravitreal triamcinolone acetonide for choroidal neovascularization

PURPOSE

To examine combined photodynamic therapy (PDT) with verteporfin and intravitreal triamcinolone acetonide for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

DESIGN

Noncomparative case series.

PARTICIPANTS

Twenty-six eyes of 26 patients with CNV secondary to AMD. Thirteen with CNV, without restriction to type, were not treated with prior PDT and were called the Newly Treated group. Thirteen patients with prior PDT therapy who experienced visual loss during treatment with PDT alone comprised the remainder and were termed the Prior PDT group.

METHODS

Patients with CNV were treated with PDT immediately followed by an intravitreal injection of 4 mg of triamcinolone acetonide. Visual acuity was measured by Early Treatment Diabetic Retinopathy Study protocol refraction. Need for retreatment was based on fluorescein angiographic evidence of leakage at 3-month follow-up intervals.

MAIN OUTCOME MEASURES

Visual acuity and retreatment rate.

RESULTS

Of the 13 patients in the Newly Treated group the mean visual acuity change at 3 months was an improvement of 1.9 lines, and 4 (30.8%) had an improvement of at least 3 lines. Two patients (15.4%) required retreatment at 3 months. At the 6-month follow-up, available for 12 patients in the Newly Treated group, the mean visual acuity change from baseline was an improvement of 2.4 lines, 4 patients (33%) had an improvement of at least 3 lines and 1 patient required retreatment. At both time points the visual acuity was significantly greater than at baseline (P = 0.023 and P = 0.007, at the 3-month and 6-month time points, Wilcoxon signed ranks test) for patients in the Newly Treated group. Among the 13 patients in the Prior PDT group, the mean change in visual acuity from baseline at the 3-month follow-up was 0.31 lines and 1 patient (7.7%) had an improvement of at least 3 lines. Six-month follow-up was available for 11 patients in the Prior PDT group and the mean change from baseline visual acuity was 0.1 lines and 1 patient (9.1%) experienced an improvement of 3 or more lines. No patient in the Prior PDT group required retreatment at 3 or 6 months. At the 3-month and 6-month time points the visual acuity was not significantly different than the baseline acuity in the Prior PDT group. No patient in either group at any time point experienced a loss of visual acuity of 3 or more lines. Five patients (19.2%), 3 in the Newly Treated group and 2 in the Prior PDT group, required monodrop therapy to control their intraocular pressure. No patient developed endophthalmitis.

CONCLUSION

Although the number of patients in this pilot study was limited, the improvement of acuity and the lack of fluorescein leakage in these patients suggest combination therapy with PDT and intravitreal triamcinolone acetonide, particularly when used as first-line therapy, merits further investigation.

Age-related macular degeneration: etiology, pathogenesis, and therapeutic strategies

Age-related macular degeneration is the principal cause of registered legal blindness among those aged over 65 in the United States, western Europe, Australia, and Japan. Despite intensive research, the precise etiology of molecular events that underlie age-related macular degeneration is poorly understood. However, investigations on parallel fronts are addressing this prevalent public health problem. Sophisticated biochemical and biophysical techniques have refined our understanding of the pathobiology of drusen, geographic atrophy, and retinal pigment epithelial detachments. Epidemiological identification of risk factors has facilitated an intelligent search for underlying mechanisms and fueled clinical investigation of behavior modification. Gene searches have not only brought us to the cusp of identifying the culpable gene loci in age-related macular degeneration, but also localized genes responsible for other macular dystrophies. Recent and ongoing investigations, often cued by tumor biology, have revealed an important role for various growth factors, particularly in the neovascular form of the condition. Transgenic and knockout studies have provided important mechanistic insights into the development of choroidal neovascularization, the principal cause of vision loss in age-related macular degeneration. This in turn has culminated in preclinical and clinical trials of directed molecular interventions.

Intravitreal triamcinolone acetonide for exudative age related macular degeneration

AIM

To evaluate the effect of intravitreal triamcinolone acetonide on the visual acuity of patients with exudative age related macular degeneration, to assess the duration of a possible effect, and to evaluate clinical side effects of the treatment.

METHODS

The study included 67 patients (71 eyes) who presented with exudative age related macular degeneration of predominantly or total occult type (n = 68) or classic type (n = 3), and who received once, or repeatedly, an intravitreal injection of 25 mg of crystalline triamcinolone acetonide. Mean follow up time was 7.46 (SD 3.54) months (range 3.1-19.57 months).

RESULTS

Visual acuity increased significantly (p <0.001) from 0.16 (0.11) to a mean maximum of 0.23 (0.17). Postoperative visual acuity was highest 1-3 months after the injection. 47 (66.2%) eyes gained in maximal visual acuity and 11 (15.5%) eyes lost in visual acuity. Intraocular pressure increased significantly (p <0.001) from 15.1 (3.1) mm Hg at baseline to a maximal value of 23.0 (8.25) mm Hg. At the end of follow up, intraocular pressure again decreased significantly (p<0.001) to 16.8 (4.9) mm Hg. No cases of postoperative infectious endophthalmitis, rhegmatogenous retinal detachment, or proliferative vitreoretinopathy occurred. Owing to a decrease in visual acuity after an initial increase, six patients received a second intravitreal triamcinolone acetonide injection after which visual acuity increased again in three eyes.

CONCLUSIONS

Intravitreal injection of 25 mg of crystalline triamcinolone acetonide merits further study for the treatment of exudative age related macular degeneration.

Intraocular pressure after intravitreal injection of triamcinolone acetonide

AIM

To investigate the intraocular pressure (IOP) response after intravitreal injections of triamcinolone acetonide as treatment of intraocular neovascular or oedematous diseases.

METHODS

The prospective consecutive non-comparative interventional case series study included 71 patients (75 eyes) with progressive exudative age related macular degeneration (n = 64 eyes) or diffuse diabetic macular oedema (n = 11 eyes), who received an intravitreal injection of 25 mg triamcinolone acetonide. Mean follow up time was 6.86 (SD 2.52) months (range 3.1-14.47 months).

RESULTS

IOP increased significantly (p<0.001) from 15.43 (3.26) mm Hg preoperatively to a mean maximum of 23.38 (8.37) mm Hg (range 13-64 mm Hg) postoperatively. An IOP rise to values higher than 21 mm Hg was observed in 39 (52%) eyes. Elevation of IOP occurred about 2 months after the injection. Preoperative predictive factor for the rise in IOP was younger age (p=0.013). It was statistically independent of refractive error, presence of diabetes mellitus, and indication for the injection. In all but one eye, IOP could be lowered to the normal range with topical medication, without development of glaucomatous optic nerve head changes. In the eyes with an elevation of IOP, IOP normalised about 6 months after the injection, without further medication. Eyes undergoing repeatedly intravitreal injections of triamcinolone acetonide showed only an elevation of IOP, if after the first injection a rise of IOP had occurred.

CONCLUSIONS

After intravitreal injections of 25 mg of triamcinolone acetonide, an IOP elevation can develop in about 50% of eyes, starting about 1-2 months after the injection. In the vast majority, IOP can be normalised by topical medication, and returns to normal values without further medication about 6 months after the injection.

Intravitreal triamcinolone acetonide for refractory chronic pseudophakic cystoid macular edema

PURPOSE

To determine the safety and efficacy of intravitreal triamcinolone acetonide (TAAC) injections in patients with refractory cystoid macular edema (CME) after cataract extraction.

SETTING

LSU Eye Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.

METHODS

In this nonrandomized retrospective case review, 8 eyes of 8 patients with a history of pseudophakic CME recalcitrant to current standard treatment modalities were enrolled. The mean duration of the CME was 20 months. The patients received intravitreal injections of 1 mg of TAAC and were followed for a mean of 8 months. The main outcome measures included visual acuity, the presence of CME on biomicroscopic examination, angiographic evidence of perifoveal leakage, intraocular pressure (IOP), and complications related to treatment.

RESULTS

The visual acuity increased in all patients. The magnitude of improvement was mainly restricted by underlying macular pathology and correlated well with the level of visual acuity at entry into the study. Angiographic improvement occurred in all patients. Temporary increases in IOP were easily controlled with topical medications. No other adverse effects could be attributed to this technique. Repeated injections were required.

CONCLUSIONS

Intravitreal administration of TAAC was safe and effective in recalcitrant cases of pseudophakic CME with a beneficial effect on the macular edema and visual acuity. A prospective randomized study is needed to determine with accuracy the efficacy, safety, and exact timing of this technique and possibly to recognize subtypes with a more favorable response. Repeated injections were required in all eyes. The development of a sustained-release intravitreal drug-delivery system would be beneficial.

An immunosuppressive effect by synthetic sulfonolipids deduced from sulfonoquinovosyl diacylglycerols of sea urchin

BACKGROUND

It is important to develop new immunosuppressive agents without clinical drawbacks. In this article, we reveal the possibility of a chemically synthetic sulfonolipid that acts as a novel immunosuppressive drug.

METHODS

We evaluated the immunosuppressive effect of 3-O-(6-deoxy-6-sulfono-beta-D-glucopyranosyl)-1,2-di-O-acylglycerol (beta-SQDG) that contains a saturated C18 fatty acid, which is designated as beta-SQDG(18:0) by mixed lymphocyte reaction (MLR) and rat allogeneic skin graft. Then, we investigated the mechanism of immunosuppressive effect of beta-SQDG(18:0).

RESULTS

beta-SQDG(18:0) inhibited human MLR in a dose-dependent manner without overt cytotoxic effect and prolonged rat skin allograft rejection in vivo. beta-SQDG(18:0) did not inhibit the direct activation of responder T. This reagent could not affect the expression of either major histocompatibility antigen complex (MHC) class I or class II molecules on the cell surface of the stimulator cells, antigen-presenting cells. In contrast, beta-SQDG(18:0) was demonstrated to inhibit the binding among allogeneic lymphocytes. However, the expression of known cell surface accessory and adhesion molecules, such as CD4, CD28, leukocyte function-associated antigen 1, intercellular adhesion molecule 1, and CTLA-4, was not affected by beta-SQDG(18:0) treatment.

CONCLUSIONS

beta-SQDG(18:0) might be a new class of the immunosuppressive reagent, and the inhibition of responder T-lymphocyte activation in MLR by beta-SQDG(18:0) may be responsible for certain three-dimensional structures of this reagent or its quinovose binding to sulfonic acid.

Intravitreal triamcinolone in subfoveal recurrence of choroidal neovascularisation after laser treatment in macular degeneration

BACKGROUND

Laser treatment of extrafoveal well delineated choroidal neovascularisation in exudative age related macular degeneration has a high rate of failure with subsequent severe vision loss from subfoveal involvement. Laser treatment may limit scotoma size, but is unpalatable because of early persistent vision loss. Intravitreal triamacinolone injection may be an acceptable alternative therapy in such disparate cases.

METHODS

14 consecutive patients with recurrent neovascularisation were treated with a single 4.0 mg injection of triamacinolone and followed for up to 1 year. Visual results were compared with published data from the Macular Photocoagulation Study of recurrent neovascularisation.

RESULTS

Mean visual acuity remained stable at about 20/200 throughout the study period in the treated patients. This is comparable to the outcomes in the Macular Photocoagulation Study for laser retreated patients, and better than the observation group.

CONCLUSIONS

Intravitreal triamcinolone may be an acceptable treatment of subfoveal recurrent neovascularisation while avoiding early persistent vision loss from laser retreatment.

Effects of triamcinolone acetonide on microglial morphology and quantitative expression of MHC-II in exudative age-related macular degeneration

Animal models, in vitro assays and pilot clinical studies suggest that intravitreal triamcinolone acetonide may be useful in the treatment of age-related macular degeneration. The present case study reports the effect of intravitreal triamcinolone acetonide injection on a subretinal neovascular lesion, microglial morphology and quantitative expression of MHC-II antigens. Triamcinolone acetonide significantly decreased MHC-II expression consistent with immunocytochemical observations which revealed condensed microglial morphology. The modulation of subretinal oedema and microglial morphology correlates with in vitro observations suggesting that downregulation of inflammatory markers and endothelial cell permeability are significant features of the mode of action of triamcinolone acetonide.

Immunological and aetiological aspects of macular degeneration

Aetiological and immunological aspects of AMD, a leading cause of blindness in Western countries, have been reviewed. Developmental studies suggest that anatomical features unique to the fovea result in a critical relationship between metabolic demand and blood supply at the macula, which is maintained throughout life. Recent studies show a sufficient degree of consistency in the link between smoking and both dry and wet AMD to regard it as causative. Dry AMD is considered to be the natural endstage of the disease; epidemiological and morphological studies point to choroidal vascular atrophy as the causative event and it is suggested that signals associated with acute vascular compromise lead to the development of subretinal neovascularisation. The relationship between sub-pigment epithelial deposits, including basal laminar deposit, and the pathogenesis of AMD is examined. Much of the literature is consistent with a choroidal origin for the constituents of drusen. The blood-retinal barrier preserves the physiological environment of the neural retina and limits inflammatory responses. The factors, including cytokines, adhesion molecules and the presence of resident immunocompetent cells (microglia), which determine the immune status of the retina are considered. Historical descriptions of the involvement of inflammatory cells are provided, evidence implicating inflammation in the pathogenesis of AMD involving macrophages, giant cells and microglia has been derived from observations of human and animal subretinal neovascular lesions. The role of humoral factors such as anti-retinal autoantibodies and acute phase proteins together with clinical observations has been surveyed. Taken together these data demonstrate the involvement of both cellular and humoral immunity in the pathogenesis of AMD. It remains to be determined to what degree the influence of immunity is causative or contributory in both wet and dry AMD, however, the use of anti-inflammatory agents to ameliorate the condition further indicates the existence of an inflammatory component.