MARCONY RODRIGUES DE SANTHIAGO
Projetos de Pesquisa
Unidades Organizacionais
LIM/33 - Laboratório de Oftalmologia, Hospital das Clínicas, Faculdade de Medicina
31 resultados
Resultados de Busca
Agora exibindo 1 - 10 de 31
- OCT Study of the Femtosecond Laser Opaque Bubble Layer(2017) MARINO, Gustavo K.; SANTHIAGO, Marcony R.; WILSON, Steven E.PURPOSE: To characterize the location and regularity of the opaque bubble layer (OBL) in the corneal stroma after femtosecond laser-assisted LASIK (FS-LASIK) flap generation. METHODS: In this prospective study, 30 eyes of 15 patients who had FS-LASIK surgery for myopia, astigmatism, and/or hyperopia were included. Screen captures were obtained at the end of the flap creation and the eyes with hard type OBL were immediately imaged with anterior segment optical coherence tomography. RESULTS: The mean age of the 9 men and 6 women was 40 +/- 11.3 years (range: 22 to 60 years). Seven eyes (23.3%) developed hard type OBL that was typically localized in the central cornea beneath the LASIK flap and, in the majority of cases, located close to the hinge of the flap. Three of the seven eyes had OBL only within the laser cut, whereas the four other eyes had OBL in a spotty distribution within the stromal bed beneath the flap. None of the eyes had an accumulation of OBL within the flap itself. CONCLUSIONS: The excimer laser ablation of a stroma with OBL may be different from that of a stroma without OBL. Management of OBL when it occurs due to flap production, including allowing the bubble to dissipate when they overlie the pupil, is important to obtain the best outcomes with femtosecond laser-assisted LASIK.
- Regeneration of Defective Epithelial Basement Membrane and Restoration of Corneal Transparency After Photorefractive Keratectomy(2017) MARINO, Gustavo K.; SANTHIAGO, Marcony R.; SANTHANAM, Abirami; TORRICELLI, Andre A. M.; WILSON, Steven E.PURPOSE: To study regeneration of the normal ultrastructure of the epithelial basement membrane (EBM) in rabbit corneas that had -9.00 D photorefractive keratectomy (PRK) and developed late haze (fibrosis) with restoration of transparency over 1 to 4 months after surgery and in corneas that had incisional wounds. METHODS: Twenty-four rabbits had one of their eyes included in one of the two procedure groups (-9.00 D PRK or nearly full-thickness incisional wounds), whereas the opposite eyes served as the unwounded control group. All corneas were evaluated with slit-lamp photographs, transmission electron microscopy, and immunohistochemistry for the myofibroblast marker alpha-smooth muscle actin and collagen type III. RESULTS: In the -9.00 D PRK group, corneas at 1 month after surgery had dense corneal haze and no evidence of regenerated EBM ultrastructure. However, by 2 months after surgery small areas of stromal clearing began to appear within the confluent opacity (lacunae), and these corresponded to small islands of normally regenerated EBM detected within a larger area of the excimer laser-ablated zone with no evidence of normal EBM. By 4 months after surgery, the EBM was fully regenerated and the corneal transparency was completely restored in the ablated zone. In the incisional wound group, the two dense, linear corneal opacities were observed at 1 month after surgery and progressively faded by 2 and 3 months after surgery. The EBM ultrastructure was fully regenerated at the site of the incisions, including around epithelial plugs that extended into the stroma, by 1 month after surgery in all eyes. CONCLUSIONS: In the rabbit model, spontaneous resolution of corneal fibrosis (haze) after high correction PRK is triggered by regeneration of EBM with normal ultrastructure in the excimer laser-ablated zone. Conversely, incisional wounds heal in rabbit corneas without the development of myofibroblasts because the EBM regenerates normally by 1 month after surgery.
- Phototherapeutic Keratectomy: Science and Art(2017) WILSON, Steven E.; MARINO, Gustavo K.; MEDEIROS, Carla S.; SANTHIAGO, Marcony R.PURPOSE: To describe, with videos, the principles of excimer laser phototherapeutic keratectomy (PTK) for the treatment of corneal scars, corneal surface irregularity, and recurrent corneal erosions. METHODS: Depending on the pathology in a treated cornea, the epithelium is removed either by transepithelial PTK ablation with the excimer laser or thorough scraping with a scalpel blade. Stromal PTK can be performed with or without photorefractive keratectomy (PRK), depending on the refractive status of both eyes. Residual surface irregularity is treated with masking-smoothing PTK. Typically, 0.02% mitomycin C treatment is applied for 30 seconds to corneas treated with PTK for scars and surface irregularity. RESULTS: Transepithelial PTK with masking-smoothing typically improves corrected distance visual acuity in the eye even if the entire stromal opacity cannot be removed and can be used to debulk surface irregularity to facilitate subsequent therapeutic customized wavefront-guided or optical coherence tomography-guided PTK or PRK. PTK for recurrent erosion is performed after thorough mechanical epithelial debridement of redundant epithelial basement membrane (EBM) with a scalpel and should only include a dusting of excimer laser to remove residual EBM without inducing central irregular astigmatism or damaging limbal tissues. Meta-analyses are provided for PTK treatment for corneal scars, corneal dystrophies, and recurrent corneal erosions. CONCLUSIONS: Excimer laser PTK is a highly effective treatment for superficial corneal scars, central corneal irregular astigmatism, and recurrent corneal erosions unresponsive to medical treatment or mechanical epithelial debridement alone.
- Topical Losartan Decreases Myofibroblast Generation But Not Corneal Opacity After Surface Blast-Simulating Irregular PTK in Rabbits(2023) SAMPAIO, Lycia Pedral; VILLABONA-MARTINEZ, Valeria; SHIJU, Thomas Michael; SANTHIAGO, Marcony R.; WILSON, Steven E.Purpose: To evaluate the efficacy of topical losartan after blast injury-simulating irregular phototherapeutic keratectomy (PTK) in rabbits.Methods: Twelve NZW rabbits underwent 100 pulse 6.5 mm diameter PTK over a metal screen to generate severe surface irregularity and inhibit epithelial basement membrane regeneration. Corneas were treated with 0.8 mg/mL losartan in balanced salt solution (BSS) or BSS 50 mu L six times per day for six weeks after PTK. All corneas had slit lamp photography, with and without 1% fluorescein at two, four, and six weeks after PTK, and were analyzed using immunohistochemistry for the myofibroblast marker alpha-smooth muscle actin (alpha-SMA), keratocyte marker keratocan, mesenchymal cell marker vimentin, transforming growth factor (TGF)-beta 1, and collagen type IV.Results: Topical 0.8 mg/mL losartan six times a day significantly decreased anterior stromal alpha-SMA intensity units compared to BSS at six weeks after anterior stromal irregularity-inducing screened PTK (P = 0.009). Central corneal opacity, however, was not significantly different between the two groups. Keratocan, vimentin, TGF-beta 1, or collagen type IV levels in the anterior stroma were not significantly different between the two groups.Conclusions: Topical losartan effectively decreased myofibroblast generation after surface blast simulation irregular PTK. However, these results suggest initial maskingsmoothing PTK, along with adjuvant topical losartan therapy, may be needed to decrease corneal stromal opacity after traumatic injuries that produce severe surface irregularity.Translational Relevance: Topical losartan decreased scar-producing stromal myofibroblasts after irregular PTK over a metal screen but early smoothing of irregularity would also likely be needed to significantly decrease corneal opacity.
- Losartan Inhibition of Myofibroblast Generation and Late Haze (Scarring Fibrosis) After PRK in Rabbits(2022) SAMPAIO, Lycia Pedral; HILGERT, Guilherme S. L.; SHIJU, Thomas Michael; SANTHIAGO, Marcony R.; WILSON, Steven E.PURPOSE: To study the effect of topical losartan compared to vehicle on the generation of myofibroblasts and development of late haze scarring fibrosis after photorefractive keratectomy (PRK) in rabbits. METHODS: Twelve rabbits had-9.00 diopter (D) PRK in one eye followed by 50 mu L of topical 0.2 mg/mL losartan or 50 mu L of vehicle six times per day for 1 month. Standardized slit lamp photographs were obtained prior to death. Duplex immunohistochemistry was performed on cryofixed corneas for myofibroblast marker alpha-smooth muscle actin (a-SMA) and keratocyte marker keratocan or collagen type IV and transforming growth factor (TGF)-I31. ImageJ software (National Institutes of Health) was used for quantitation. RESULTS: Topical losartan compared to vehicle significantly decreased corneal opacity (P = .04) and anterior stromal myofibroblast generation (P = .01) at 1 month after PRK. Topical losartan compared to vehicle also decreased anterior stromal non-basement membrane collagen type IV at 1 month after PRK (P = .004). CONCLUSIONS: Topical angiotensin converting enzyme II receptor inhibitor losartan, a known inhibitor of TGF-I3 signaling, decreased late haze scarring fibrosis and myofibroblast generation after-9.00 D PRK in rabbits compared to vehicle. It also decreases TGF-I3-modulated, corneal fibroblast-produced, non-basement membrane stromal collagen type IV-likely also through inhibition of TGF-I3 signaling.[J Refract Surg. 2022;38(12):820-829.]
conferenceObject Descemet's basement membrane modulation of corneal fibrosis(2019) WILSON, Steven E.; MEDEIROS, Carla S.; SAIKIA, Paramananda; OLIVEIRA, Rodrigo Carlos de; LASSANCE, Luciana; SANTHIAGO, Marcony R.- Association Between the Percent Tissue Altered and Post-Laser In Situ Keratomileusis Ectasia in Eyes With Normal Preoperative Topography(2014) SANTHIAGO, Marcony R.; SMADJA, David; GOMES, Beatriz F.; MELLO, Glauco R.; MONTEIRO, Mario L. R.; WILSON, Steven E.; RANDLEMAN, J. BradleyPURPOSE: To investigate the association of a novel metric, percent tissue altered, with the occurrence of ectasia after laser in situ keratomileusis (LASIK) in eyes with normal corneal topography and to compare this metric with other recognized risk factors. DESIGN: Retrospective case-control study. METHODS: The study included 30 eyes from 16 patients with bilateral normal preoperative Placido-based corneal topography that developed ectasia after LASIK (ectasia group) and 174 eyes from 88 consecutive patients with uncomplicated LASIK and at least 3 years of postoperative follow-up. The following metrics were evaluated: age, preoperative central corneal thickness, residual stromal bed, Ectasia Risk Score System scores, and percent tissue altered, derived from [PTA = (FT + AD)/CCT], where FT = flap thickness, AD = ablation depth, and CCT = preoperative central corneal thickness. RESULTS: In the ectasia group, percent tissue altered >= 40 was the most prevalent factor (97%), followed by age < 30 years (63%), residual stromal bed <= 300 mu m (57%), and ectasia risk score >= 3 (43%) (P < .001 for all). Percent tissue altered >= 40 had the highest odds ratio (223), followed by residual stromal bed <= 300 mu m (74) and ectasia risk score >= 4 (8). Stepwise logistic regression revealed percent tissue altered >= 40 as the single most significant independent variable (P < .0001). CONCLUSIONS: Percent tissue altered at the time of LASIK was significantly associated with the development of ectasia in eyes with normal preoperative topography and was a more robust indicator of risk than all other variables in this patient population.
- The Corneal Basement Membranes and Stromal Fibrosis(2018) MEDEIROS, Carla S.; MARINO, Gustavo K.; SANTHIAGO, Marcony R.; WILSON, Steven E.PURPOSE. The purpose of this review was to provide detailed insights into the pathophysiology of myofibroblast-mediated fibrosis (scarring or late haze) after corneal injury, surgery, or infection. METHOD. Literature review. RESULTS. The epithelium and epithelial basement membrane (EBM) and/or endothelium and Descemet's basement membrane (BM) are commonly disrupted after corneal injuries, surgeries, and infections. Regeneration of these critical regulatory structures relies on the coordinated production of BM components, including laminins, nidogens, perlecan, and collagen type IV by epithelial, endothelial, and keratocyte cells. Whether a cornea, or an area in the cornea, heals with transparency or fibrosis may be determined by whether there is injury to one or both corneal basement membranes (EBM and/or Descemet's BM) and delayed or defective regeneration or replacement of the BM. These opaque myofibroblasts, and the disordered extracellular matrix these cells produce, persist in the stroma until the EBM and/or Descemet's BM is regenerated or replaced. CONCLUSIONS. Corneal stromal fibrosis (also termed ""stromal scarring'' or ""late haze'') occurs as a consequence of BM injury and defective regeneration in both the anterior (EBM) and posterior (Descemet's BM) cornea. The resolution of fibrosis and return of stromal transparency depends on reestablished BM structure and function. It is hypothesized that defective regeneration of the EBM or Descemet's BM allows key profibrotic growth factors, including transforming growth factor beta-1 (TGF-beta 1) and TGF-beta 2, to penetrate the stroma at sustained levels necessary to drive the development and maintenance of mature opacity-producing myofibroblasts from myofibroblast precursors cells, and studies suggest that perlecan and collagen type IV are the critical components in EBM and Descemet's BM that bind TGF-beta 1, TGF-beta 2, platelet-derived growth factor, and possibly other growth factors, and regulate their bioavailability and function during homeostasis and corneal wound healing.
- Pathophysiology of Corneal Scarring in Persistent Epithelial Defects After PRK and Other Corneal Injuries(2018) WILSON, Steven E.; MEDEIROS, Carla S.; SANTHIAGO, Marcony R.PURPOSE: To analyze corneal persistent epithelial defects that occurred at 3 to 4 weeks after -4.50 diopter (D) photorefractive keratectomy (PRK) in rabbits and apply this pathophysiology to the treatment of persistent epithelial defects that occur after any corneal manipulations or diseases. METHODS: Two of 168 corneas that had -4.50 D PRK to study epithelial basement membrane regeneration developed spontaneous persistent epithelial defects that did not heal at 3 weeks after PRK. These were studied with slit-lamp photographs, immunohistochemistry for the myofibroblast marker alpha-smooth muscle actin (alpha-SMA), and transmission electron microscopy. RESULTS: Myofibroblasts developed at the stromal surface within the persistent epithelial defect and for a short distance peripheral to the leading edge of the epithelium. No normal epithelial basement membrane was detectable within the persistent epithelial defect or for up to 0.3 mm behind the leading edge of the epithelium, although epithelial basement membrane had normally regenerated in other areas of the zone ablated by an excimer laser where the epithelium healed promptly. CONCLUSIONS: A persistent epithelial defect in the cornea results in the development of myofibroblasts and disordered extracellular matrix produced by these cells that together cause opacity within, and a short distance beyond, the persistent epithelial defect. Clinicians should treat persistent epithelial defects within 10 days of non-closure of the epithelium to facilitate epithelial healing to prevent long-term stromal scarring (fibrosis).
article 20 Citação(ões) na Scopus Association Between the Percent Tissue Altered and Post-Laser In Situ Keratomileusis Ectasia in Eyes With Normal Preoperative Topography REPLY(2014) SANTHIAGO, Marcony R.; SMADJA, David; GOMES, Beatriz F.; MELLO, Glauco R.; MONTEIRO, Mario L. R.; WILSON, Steven E.; RANDLEMAN, J. Bradley