Marcelle Giasson

Reconstructed Human Cornea Produced in vitro by Tissue Engineering

The aim of the present study was to produce a reconstructed human cornea in vitro by tissue engineering and to characterize the expression of integrins and basement membrane proteins in this reconstructed cornea. Epithelial cells and fibroblasts were isolated from human corneas (limbus or centre) and cultured on plastic substrates in vitro. Reconstructed human corneas were obtained by culturing epithelial cells on collagen gels containing fibroblasts. Histological (Masson’s trichrome staining) and immunohistological (laminin, type VII collagen, fibronectin as well as β1, α3, α4, α5, and α6 integrin subunits) studies were performed. Human corneal epithelial cells from the limbus yielded colonies of small fast-growing cells when cultured on plastic substrates. They could be subcultured for several passages in contrast to central corneal cells. In reconstructed cornea, the epithelium had 4–5 cell layers by the third day of culture; basal cells were cuboidal. The basement membrane components were already detected after 3 days of culture. Integrin stainings, except for the α4 integrin, were also positive after 3 days. They were mostly detected at the epithelium-stroma junction. Such in vitro tissue-engineered human cornea, which shows appropriate histology and expression of basement membrane components and integrins, provides tools for further physiological, toxicological and pharmacological studies as well as being an attractive model for gene expression studies.

Prospective randomized trial: outcomes of SF6 versus C3F8 in macular hole surgery

OBJECTIVE To compare macular hole (MH) closure and visual acuity improvement after vitrectomy using SF6 versus C3F8 gas tamponade. The secondary purposes were to report the cumulative incidence of cataract development at 1 year after MH surgery and the proportion of complications. DESIGN Prospective, randomized study. PARTICIPANTS Thirty-one patients were prospectively randomized to the SF6 group and 28 patients to the C3F8 group. METHODS Preoperative data included MH minimum diameter, Early Treatment Diabetic Retinopathy Study (ETDRS) best corrected visual acuity (BCVA), cataract staging, and intraocular pressure (IOP) measurement. Postoperative data included optical coherence tomography confirmation of the closure at 6 weeks and 1 year, and ETDRS BCVA and cataract development/extraction, both 1 year after the MH surgery. RESULTS Primary MH closure was achieved in 93.3% in the SF6 group and 92.9% in the C3F8 group. Mean ETDRS BCVA improved by 17.7 letters in the SF6 and 16.9 letters in the C3F8 group. The difference in cumulative incidence of cataract development and extraction between both groups was not statistically significant. Regardless of the dye used, similar results were achieved. Finally, the proportion of adverse events was similar in both groups. CONCLUSIONS MH surgery with SF6 gas achieves results similar to C3F8 in terms of visual acuity improvement, MH closure, cataract development/extraction, and adverse events.

Selective inhibition of spermatogenesis in the presence of normal libido following combined treatment with an LHRH agonist and testosterone in the dog

In order to maintain libido in dogs treated with an LHRH agonist, animals were administered with testosterone in a gel form for percutaneous adsorption. Histological aspect of testis indicate a complete blockade of spermatogenesis after treatment with the LHRH agonist and the addition of testosterone to these animals did not restore the spermatogenesis. The measurement of testicular steroid levels showed that following LHRH-A administration, the concentration of androgens in testis remained low in the presence or absence of testosterone supplement. However, the prostate weight as well as the volume of ejaculate returned to normal when testosterone was added and this observation can be correlated with the high amount of androgens in prostate. The present study supports the use of LHRH agonist in combination with testosterone as a selective method for inhibition of spermatogenesis in the male.

Retinal function assessment of trypan blue versus indocyanine green assisted internal limiting membrane peeling during macular hole surgery.

OBJECTIVE To compare multifocal electroretinography (mfERG) retinal function and the anatomical and visual outcomes of macular hole surgery performed with indocyanine green (ICG) or trypan blue (TB). DESIGN Prospective, randomized study. PARTICIPANTS Twenty-five eyes of 24 patients. METHODS Patients underwent a pars plana vitrectomy with removal of the internal limiting membrane. In 14 eyes, internal limiting membrane visualization during macular hole repair was performed using TB, and ICG was used in 11 eyes. The examination protocol (performed before surgery and at 3 weeks, 3 months, 6 months, and 12 months after surgery) included optical coherence tomography, mfERG (mfERG-103 hexagons), and assessment of best corrected visual acuity (BCVA) and contrast sensitivity (CS). RESULTS Closure of macular hole was achieved in 100% of the cases. In the TB group, P1 amplitude and implicit time improved significantly at 12 months after surgery (P < 0.05), whereas in the ICG group, significant improvement occurred at both 6 (P < 0.05) and 12 months (P < 0.01). BCVA improved significantly in both groups at 6 and 12 months (P < 0.01). Both groups also showed a statistically significant CS improvement at spatial frequency of 6 cycles per degree (P = 0.01) 1 year postoperatively. At 12 months, improvement of P1 amplitude and implicit time, BCVA, and CS was not different between groups. CONCLUSIONS In this study, the use of TB or ICG appears to yield similar improvement in terms of BCVA, CS, and mfERG amplitude and implicit time changes at 12 months.

Bevacizumab and ranibizumab for neovascular age-related macular degeneration: a treatment approach based on individual patient needs

OBJECTIVE To compare the efficacy of intravitreal bevacizumab and ranibizumab for the treatment of neovascular age-related macular degeneration using an as-needed treatment regimen. DESIGN Retrospective chart review. PARTICIPANTS One hundred and ninety two eyes of 184 patients. METHODS Patients received an initial treatment of 3 monthly intravitreal injections of ranibizumab or bevacizumab and retreatment is individually considered for each patient on the basis of optical coherence tomography, angiography, and clinical examination. RESULTS Fifty eyes treated with ranibizumab and 142 eyes treated with bevacizumab were included. The average age of the patients at baseline was 76.9 ± 8 years and 76.4 ± 8 years in the ranibizumab and bevacizumab group respectively. Mean visual acuity improved from 0.69 to 0.55 logMAR at 12 months in the ranibizumab group and from 0.70 to 0.67 logMAR in the bevacizumab group. At 12 months, 92% of eyes treated with ranibizumab had lost fewer than 0.3 logMAR, as compared with 83% in the bevacizumab group. The ranibizumab group received a mean of 4.92 injections, compared to 4.75 injections in the bevacizumab group over 12 months. After the first 3 injections, 20% of patients in the ranibizumab group and 26% in the bevacizumab group never needed another injection. CONCLUSIONS An approach based on clinical onset and choroidal neovascularization progression at angiography may provide benefit by reducing the number of intravitreal injections required.