Giant retinal pigment epithelium tears with membranous nephropathy: a case report and literature review.

BACKGROUND: Kidney and eye diseases may be closely linked. Tears of the retinal pigment epithelium (RPE) have been reported to be related to kidney diseases, such as IgA nephropathy and light-chain deposition disease. However, pigment epithelium tears associated with membranous nephropathy have not been reported or systematically analysed. CASE PRESENTATION: A 68-year-old man presented with decreased right eye visual acuity. Optical coherence tomography (OCT) revealed cystic macular edema, localized serous detachment of the retina and loss of the outer retinal structure in the right eye and retinal pigment epithelium detachment (PED) combined with serous detachment of the retina in the left eye. Fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) revealed giant RPE tears in the right eye and exudative age-related macular degeneration in the left eye. The patient also suffered from severe membranous nephropathy-autoimmune glomerulonephritis. Renal biopsy immunofluorescence revealed a roughly granular pattern, with immunoglobulin G (IgA), immunoglobulin G (IgG), IgM, complement C3(Components 3), λ light chain and κ light chain subepithelial staining. CONCLUSIONS: It is hypothesized that severe membranous nephropathy caused immune complex deposition on the surface of Bruch membrane, resulting in weakened adhesion between the RPE and Bruch membrane and impaired RPE pump function, combined with age-related macular degeneration, leading to giant RPE tears in the right eye. Close attention should be given to the ocular condition of patients with membranous nephropathy to facilitate timely treatment and avoid serious consequences.

3D printed fibroblast-loaded hydrogel for scleral remodeling to prevent the progression of myopia.

Pathologic myopia has seriously jeopardized the visual health of adolescents in the past decades. The progression of high myopia is associated with a decrease in collagen aggregation and thinning of the sclera, which ultimately leads to longer eye axis length and image formation in front of the retina. Herein, we report a fibroblast-loaded hydrogel as a posterior scleral reinforcement (PSR) surgery implant for the prevention of myopia progression. The fibroblast-loaded gelatin methacrylate (GelMA)-poly(ethylene glycol) diacrylate (PEGDA) hydrogel was prepared through bioprinting with digital light processing (DLP). The introduction of the PEGDA component endowed the GelMA-PEGDA hydrogel with a high compression modulus for PRS surgery. The encapsulated fibroblasts could consistently maintain a high survival rate during 7 days of in vitro incubation, and could normally secrete collagen type I. Eventually, both the hydrogel and fibroblast-loaded hydrogel demonstrated an effective shortening of the myopic eye axis length in a guinea pig model of visual deprivation over three weeks after implantation, and the sclera thickness of myopic guinea pigs became significantly thicker after 4 weeks, verifying the success of sclera remodeling and showing that myopic progression was effectively controlled. In particular, the fibroblast-loaded hydrogel demonstrated the best therapeutic effect through the synergistic effect of cell therapy and PSR surgery.

Visual outcome of 25 Gauge vitrectomy for acute post operative infectious endophthalmitis.

BACKGROUND: The correlation between the change in foveal thickness measured using optical coherence tomography (OCT) following surgery for infectious endophthalmitis and preoperative and postoperative visual acuity is uncertain, and there are few pertinent studies on this topic. OBJECTIVE: We explored the variations in macular thickness using OCT after emergency vitrectomy for post-cataract infectious endophthalmitis and the relationship between macular thickness with changes in visual function. METHODS: We included 10 cases of post-cataract infectious endophthalmitis. Each patient underwent 25-G vitrectomy. RESULTS: The infection in all 10 patients was under control and visual function improved. Postoperative vitreous humor culture was positive in 8 patients, including 7 cases of coagulase-negative Staphylococcus epidermidis and 1 case of Lactobacillus acidophilus. The average age of these 10 patients was 71.60 ± 8.71 years (P< 0.05, two-tailed). There was no significant correlation between time 2 (the time of onset after cataract surgery) and visual prognosis. The average time 1 (the time of the vitrification surgery caused by the onset of the disease) was 1.45 ± 0.76 days (P< 0.05, two-tailed). The postoperative 3dVA ranged from 0.20 to 3.00, with an average visual acuity of 1.87 ± 1.12, which was superior to the preoperative value (P< 0.01, two-tailed). The correlation between the post3dVA and post 1mVA was significant. The post 1mVA ranged from 0.05 to 2.20, with an average visual acuity of 0.94 ± 0.74 (P< 0.05, two-tailed). The correlation between post 1mVA and post3mVA was significant. Also, paired t-tests comparing preoperative and postoperative visual acuity revealed a significant correlation (P< 0.05, two-tailed). The post3mVA was 0-1.00 with an average visual acuity of 0.44 ± 0.41. The postoperative foveal thickness ranged from 176.00 to 514.00 µm, with an average thickness of 281.10 ± 113.12 µm. CONCLUSION: Emergency 25-G minimally invasive vitrectomy can improve visual acuity and decrease the reoperation rate for patients who have acquired post-cataract infectious endophthalmitis. There were significant correlations between age, disease onset to operation time, preoperative and postoperative visual acuity, and postoperative macular thickness.

Lactobacillus acidophilus Endophthalmitis Postcataract Operation: A Case Report with a Literature Review.

BACKGROUND: Lactobacillus acidophilus is usually considered nonpathogenic and widely distributed in the human gastrointestinal and vaginal tract. In rare cases, lactobacilli may cause eye infections. CASE PRESENTATION: We report a 71-year-old man who experienced unexpected ocular pain and decreased visual acuity for one day after cataract surgery. He presented with obvious conjunctival and circumciliary congestion, corneal haze, anterior chamber cells, anterior chamber empyema, posterior corneal deposits, and pupil light reflection disappearance. This patient underwent the standard three-port 23-gauge pars plana vitrectomy and received the intravitreal perfusion of vancomycin at 1 mg/0.1 mL. The culture of the vitreous fluid produced Lactobacillus acidophilus. CONCLUSION: Acute Lactobacillus acidophilus endophthalmitis can occur after cataract surgery, which should be taken into consideration.

Aqueous humor cytokine levels are associated with the severity of visual field defects in patients with primary open-angle glaucoma.

BACKGROUND: To evaluate the aqueous humor (AH) levels of cytokines in primary open-angle glaucoma (POAG) patients and cataract patients. METHODS: Thirty-eight POAG patients and 26 cataract patients were recruited. Peripheral blood (PB) was collected from each subject. The POAG group was divided into 2 subgroups according to the severity of visual field defects. The cutoff point of the mean deviation (MD) of the visual field was -12 dB. AH was obtained at the time of anterior chamber puncture during cataract or glaucoma surgery by using a 27-gauge needle attached to a microsyringe. AH and PB levels of interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta2 (TGF-ß2) and IL-4 were assayed by enzyme-linked immunosorbent assay. Postoperative intraocular pressures (IOPs) of POAG patients were recorded during the follow-up period. RESULTS: TNF-α and TGF-ß2 showed significantly higher AH levels in the POAG group than in the cataract group (P < 0.001 and P = 0.001, respectively). For the POAG group, preoperative IOPs were significantly positively correlated with AH levels of TNF-α (r2 = 0.129, P = 0.027) and TGF-ß2 (r2 = 0.273, P = 0.001). AH levels of TGF-ß2 were significantly different among cataract patients, POAG patients with MD> -12 dB and POAG patients with MD≤ -12 dB (P = 0.001). AH levels of TNF-α were significantly positively associated with IOP reduction after trabeculectomy (P = 0.025). AH and PB levels of cytokines were not related to the long-term success of trabeculectomy. CONCLUSION: The levels of TNF-α and TGF-ß2 showed different profiles in POAG patients and cataract patients. AH levels of TGF-ß2 were correlated with the severity of glaucomatous neuropathy in POAG patients. The findings suggest possible roles for cytokines in the pathogenesis and development of POAG.

Self-rescue technique and Yamane's technique in situ: Management of intraoperative haptic slippage.

Haptic slippage is a frequently encountered and technically demanding complication in Yamane's surgery. The slipped haptic could be regained when bimanual operations are workable. Management of haptic slippage is difficult when the right hand is occupied by the puncture needle, which could be solved easily with the self-rescue technique, which uses the needle tip as an intraocular instrument for better exposure and easier engagement of the slipped haptic. With the aid of bimanual operations and self-rescue technique, Yamane's technique in situ is applicable when the haptic of dislocated intraocular lens suits for flange-making.

Loratadine-associated cystoid macular edema: A case report.

Purpose: To report the first known case of bilateral cystoid macular edema in a patient undergoing long-term loratadine treatment. Observations: A 49-year-old Chinese woman who had been undergoing treatment with loratadine for the past 6 years presented with decreased visual acuity and bilateral cystoid macular edema (CME). Upon cessation of loratadine, macular edema partially resolved, and visual acuity markedly improved. Fundus autofluorescence (FAF), optical coherence tomography (OCT), and fluorescence fundus angiography (FFA) were used to document the severity of CME and its subsequent resolution after cessation of loratadine therapy. Conclusions and Importance: Long-term use of loratadine might cause CME that partially resolves with discontinuation of the drug. The pathophysiology of drug-induced CME without leakage remains unclear. Dysfunction of histamine receptor1-expressed retinal neurons and the associated signal transduction, toxicity to Müller cells or RPE cells with subsequent intracellular fluid accumulation, and subclinical damage to the blood-retina barrier leading to leakage of extracellular fluid, have been proposed.

Modified Yamane technique with a 26-gauge needle: single corneal incision and simplified haptic insertion.

A modified Yamane technique with a 26-gauge needle for aphakia correction is described. Single corneal or corneoscleral incision is set at 12 o'clock. The 26-gauge needles are used to make 2 angled incisions parallel to the limbus to fix the haptics of a 3-piece intraocular lens. The modifications provide an easier and safer way of haptic insertion into the needle tip and decreases the possibility of bending or breaking the haptic.

Characteristics of fixation patterns and their relationship with visual function of patients with idiopathic macular holes after vitrectomy.

To analyze the relationships between the fixation location and the visual function of idiopathic macular hole (IMH) patients with macular integrity assessment (MAIA) examination preoperatively and 3 months postoperatively. This was a retrospective case analysis. Forty-three eyes of 43 patients diagnosed with IMH were included in this study. The best corrected visual acuity (BCVA) assessments, optical coherence tomography (OCT) and MAIA examinations were performed before surgery and 1 week, 1 month and 3 months after surgery. The relationships between MAIA parameters and visual acuity were assessed by correlation analysis. Grouping by fixation location with the foveola (2°) as the centre, the locations could be divided into five groups, including foveolar, temporal, nasal, inferior and superior fixation. The mean macular sensitivity (MMS) of the macular area was correlated with the BCVA in the IMH patients before and 3 months after surgery (before surgery P = 0.00, after surgery P = 0.00). The MMS could be used as a good indicator for evaluating visual function in IMH patients. There was a significant difference in fixation location before and after the operation (P = 0.01). The preoperative fixation location of IMH patients was mainly in the superior area, while postoperatively moved to the foveola and nasal areas. Paying attention to the changes of fixation locations in IMH patients may provide new clues for further improving postoperative visual function.

Risk factors for glial cell proliferation after idiopathic macular hole repair with internal limiting membrane flap.

BACKGROUND: To study the influencing factors for different healing patterns of patients with idiopathic macular holes (IMH) after vitrectomy surgery performed with the internal limiting membrane (ILM) flap technique. METHODS: This study was a retrospective, consecutive, observational case series study. We recruited 52 IMH patients who underwent vitrectomy with the ILM flap technique. The participants were divided into 2 groups: group A (25 patients), without significant glial cell proliferation in the macular area on postoperative optical coherence tomography (OCT); and group B (27 patients), with significant glial cell proliferation. The postoperative visual acuity (VA), external limiting membrane (ELM) and ellipsoid zone (EZ) recovery characteristics were compared between the two groups. RESULTS: There were statistically significant differences in minimum linear diameter (MLD) of the macular hole and postoperative VA (p = 0.02, 2.81 E-4 respectively) between the two groups. Compared with patients in group A, patients in group B had poorer VA and EZ recovery in the first 12 months after surgery, and a longer ELM recovery period. The OCT results showed that patients in group B had more extensive ILM filling in the macular area after surgery than patients in group A. CONCLUSION: The presence of aberrant glial cell proliferation was related to a larger MLD of the IMH, and the filling approach for the ILM during the operation was related to the postoperative healing pattern and vision acuity.

Prompt 27-gauge sutureless transconjunctival vitrectomy for bleb-associated endophthalmitis.

PURPOSE: To summarize the characters of 6 bleb-associated endophthalmitis (BAE) cases and to report the outcomes of prompt 27-gauge sutureless transconjunctival vitrectomy to treat these cases. METHODS: Retrospective, non-randomized, consecutive case series of patients diagnosed with bleb-associated endophthalmitis who underwent prompt 27-gauge vitrectomy. RESULTS: The interval to get bleb-associated endophthalmitis from previous surgery was variant from 2 weeks to 36 months. Most of the patients experienced eye pain. The visual acuity was affected quickly. All the patients presented with hypopyon, fibrinous reaction, and vitreous wick. The size of the hypopyon was from 2 to 4 mm. Two patients came with intraocular lenses. Prompt 27-gauge sutureless transconjunctival vitrectomy was performed on all patients with bleb-associated endophthalmitis. None of the patients experienced complications of sutureless vitrectomy such as hypotony or wound leak. The improvement of best corrected visual acuity (BCVA) was significant in four of six patients. The improvement of BCVA was statistically calculated by using logMAR VA (p < 0.01). The intraocular pressure (IOP) in all six patients reduced after the surgery. At 6 months' follow-up, four patients with diffuse blebs had normal IOPs while two patients with cystic or encapsulated blebs had uncontrolled IOPs (> 21 mmHg) and received pressure-lowering agents. CONCLUSIONS: BAE is associated with substantial visual morbidity. Prompt 27-gauge sutureless transconjunctival vitrectomy is an effective and safe way for treating bleb-associated endophthalmitis.

Minimally Invasive Repetitive UVA Irradiation along with Riboflavin Treatment Increased the Strength of Sclera Collagen Cross-Linking.

OBJECTIVE: This study aimed to investigate the efficacy of minimally invasive repetitive UVA irradiation along with riboflavin treatment on sclera collagen cross-linking in rabbits. METHOD: Forty-eight healthy adult New Zealand white rabbits were randomly divided into four groups: pseudosurgery group (group I), single-irradiation group (group II), duplicate-irradiation group (group III), and triplicate-irradiation group (group IV), with 12 rabbits in each group. For the single-irradiation group, a specially made LED light source was inserted through a minimally invasive conjunctival incision to gain close contact with the sclera for irradiation, and for the repetitive irradiation groups, the above experimental procedure was repeated once or twice every other week. Biomechanical parameters of the sclera including ultimate stress (σ) and 8% Young's modulus (E) were compared among the groups. RESULTS: In comparison with control group I, the ultimate stress of group II, group III, and group IV increased by 80.1%, 107.9%, and 182.1%, respectively, and their 8% Young's modulus increased by 106.1%, 159.5%, and 208.5%, respectively, one day after surgery (P < 0.01). CONCLUSION: Repetitive minimally invasive UVA irradiation with riboflavin significantly increased biomechanical strength of the sclera in the irradiated area, and biomechanical strength increased with repeated times of irradiation.

Slit-miR-218-Robo axis regulates retinal neovascularization.

miR-218 is an important intronic microRNA (miRNA or miR) which is known to regulate angiogenesis in tumors. The present study aimed to investigate the effects of miR-218, as well as its host genes, Slit2 and Slit3, on oxygen-induced retinal neovascularization (RNV) and to explore the associated mechanisms of action. For this purpose, a mouse model of oxygen-induced retinopathy (OIR) was established. The expression levels of miR-218-1 and miR-218-2, as well as those of their host genes, Slit2 and Slit3, were determined by RT-qPCR. Fluorescein angiography was performed on the retinas of the mice with OIR, and RNV was quantified by H&E staining in order to evaluate the effect of pCDH-CMV-miR-218 intravitreal injection on RNV in the mouse model of OIR. Roundabout, axon guidance receptor, homolog 1 (Robo1) expression was detected in mouse retinal vascular endothelial cells expressing high or low levels of miR-218 and in retinal tissues from mice with OIR by western blot analysis. Cell migration was evaluated by a scratch wound assay. We noted that in the mice with OIR, the expression level of miR-218 was significantly downregulated. We also noted that Robo1 expression was suppressed by miR-218. Furthermore, in the mice with OIR, the expression level of miR-218 was significantly downregulated, and that of miR-218-1 and its host gene, Slit2, was concomitantly downregulated as well. The restoration of miR-218 inhibited retinal angiogenesis by targeting Robo1. Taken together, our findings suggest that the Slit2-miR-218-Robo1 axis contributes to the inhibition of retinal angiogenesis and that miR-218 may be a new therapeutic target for preventing RNV.

Correlation of macular choroidal thickness with concentrations of aqueous vascular endothelial growth factor in high myopia.

PURPOSE: To investigate the association of both aqueous and serum vascular endothelial growth factor (VEGF) levels and macular choroidal thickness in high myopia. MATERIALS AND METHODS: VEGF concentrations were measured in aqueous and serum samples via enzyme-linked immunosorbent assay (ELISA) and compared between high myopia (n = 36 eyes, 36 patients) and normal control (n = 42 eyes, 42 patients) eyes. Macular choroidal thickness, the distance from the retinal pigment epithelium (RPE) to the scleral interface, was determined via enhanced depth-imaging optical coherence tomography (EDI-OCT). Axial length was measured using the intraocular (IOL) lens Master. RESULTS: Aqueous levels of VEGF from high myopia patients were significantly lower compared with those from control persons (61.4 ± 27.6 versus 122.6 ± 52.4 pg/ml; p < 0.001), respectively. Macular choroidal thickness of high myopia patients was significantly lower compared with that of control persons (111.1 ± 45.0 versus 230.6 ± 81.8 µm; p < 0.001), respectively. Aqueous levels of VEGF were significantly associated with both macular choroidal thickness (R(2)= 0.641; p < 0.001) and axial length (R(2)= 0.679; p < 0.001) in high myopia patients. In addition, there was a significantly negative correlation between macular choroidal thickness and axial length (R(2)= 0.69; p < 0.001). However, no correlation between serum VEGF and either macular choroidal thickness or axial length was detected in high myopia patients (R(2)= 0.009; p = 0.59; R(2)= 0.00002; p = 0.981). CONCLUSIONS: Macular choroidal thickness was significantly correlated with aqueous, but not serum, levels of VEGF in highly myopic eyes. Macular choroidal thickness may be of predictive value for identifying aqueous VEGF levels in high myopia patients and may, thus, be a useful prognostic modality.

Platelet-derived growth factor induced alpha-smooth muscle actin expression by human retinal pigment epithelium cell.

PURPOSES: (1) To evaluate the association between expression of α-smooth muscle actin (α-SMA) in proliferative vitreoretinopathy (PVR) and the pathological grading of PVR, and the effect of platelet-derived growth factor (PDGF) on the expression of α-SMA by human retinal pigment epithelial (RPE) cells. (2) To investigate the potential induction of PDGF on the proliferation and migration of human RPE cells as well as the signaling pathways responsible. METHODS: We immunohistochemically investigated the expression of α-SMA in PVR. To further investigate the effect of PDGF and the downstream signaling, exogenous PDGF-BB and signaling inhibitors were added to cultured human RPE cells. The MTT method was performed to detected cell proliferation, while cell migration was also measured. RESULTS: α-SMA expression was positively correlated with the pathological grading of PVR. PDGF-BB could stimulate the proliferation and migration of cultured RPE cells through the participation of mitogen-activated protein kinase. In addition, PDGF induced α-SMA expression. The promotion of proliferate/migration and α-SMA expression by PDGF-BB was enhanced by the presence of serum. CONCLUSIONS: PDGF and α-SMA are 2 potential therapeutic targets for the treatment of PVR.

New modified iris suture technique for pupillary dilation in aphakic eyes during vitreoretinal surgery.

To describe a modified simple iris suture for pupillary dilation technique during vitrectomy in cases with a miotic pupil. Four translimbal incisions were created with a sharp straight blade at 1:30, 10:30, 4:30, and 7:30 o'clock, respectively. The straight needle of 10-0 polypropylene suture and a Sinskey IOL hook was used to displace the pupillary margin toward the limbus. In 3 cases, four sutures caused a 6-mm to 9-mm square-shaped pupil, and the pupil was allowed to return to a smaller size at the end of the operation. It is simple and may reduce postoperative complications.

Modulation of migration and Ca2+ signaling in retinal pigment epithelium cells by recombinant human CTGF.

PURPOSE: The migration of retinal pigment epithelium (RPE) cells is an initial step in the development of proliferative vitreoretinopathy (PVR). We investigated the expression of connective tissue growth factor (CTGF) in an in vitro model of wound healing and effects of recombinant human CTGF (rhCTGF) on modulating migration and Ca(2+) signaling in RPE cells. METHODS: Cultured human RPE monolayers were used to establish a wound-healing model. Western blot and in situ hybridization were used to detect the CTGF expression in RPE cells. Migration of RPE cells was measured under the stimulation of rhCTGF alone or in combination with dexamethasone (DEX) or 8-Br-cAMP. To determine the concentration of cytoplasmic-free Ca(2+) ([Ca(2+)]i) responding to CTGF, the fluo-3/AM-loaded RPE cells were observed with a laser scanning confocal microscope. RESULTS: The CTGF expression first increased after being wounded in RPE cells, then reached a peak and maintained at a high level. The positive expression was mainly at the edge of scrape and in motile RPE cells. rhCTGF-stimulated RPE cells migrated in a dose-dependent manner, and both DEX and 8-Br-cAMP could significantly inhibit the CTGF-induced migrations. CTGF induced a (Ca(2+))i elevation in RPE cells in a concentration-dependent manner. Moreover, stimulation of RPE cells with CTGF and DEX or 8-Br-cAMP counteracted the elevation of (Ca(2+))i induced by CTGF. CONCLUSIONS: The CTGF expression could be induced by an in vitro model of scrape wounding. rhCTGF stimulated the migration and Ca(2+) signal pathway in RPE cells in a dose-dependent manner, and DEX and 8-Br-cAMP suppressed this effect. Our results indicate that CTGF is involved in the wound-healing process and plays an important role in the pathogenesis of intraocular proliferative diseases.

Combined suture-in-needle and scleral tunnel technique for scleral fixation of intraocular lens.

We describe an intraocular lens (IOL) fixation technique that combines suture-in-needle and scleral tunnel techniques. A 10-0 polypropylene suture is inserted into the barrel of a 27-gauge sharp needle to tie the IOL haptic, and scleral tunnels are created to bury the knots for transscleral IOL fixation. The modification of the traditional scleral fixation technique simplifies the creation of a scleral covering and decreases harmful manipulations of the needle passing through the vitreous cavity.

[Experimental study of acellular xenogenic dermal matrix and allogeneic sclera as wrapping materials for hydroxy apatite implantation].

OBJECTIVE: To observe the experimental results and histopathological changes of acellular xenogenic dermal matrix (X-ADM) and allogeneic sclera used as wrapping materials of hydroxy apatite (HA) ocular implants in New Zealand white rabbits. METHODS: Twenty-four rabbits received unilateral eye enucleating and the sockets were implanted with HA spherical implants wrapped with either acellular xenogenic dermal matrix or allogeneic sclera at random. The rabbits were examined for inflammation and implant exposure and sacrificed at 1, 2, 4, 6, 8 and 12 weeks after implantation. The sockets with the grafts were exenterated and the specimens were assessed histopathologically and ultrastructurally with light or transmission electron microscopy for the changes in inflammation reaction and vascularization. RESULTS: Compared to allogeneic sclera at the same stage of implantation, acellular xenogenic dermal matrix demonstrated more active and earlier growth of fibroblasts and new vessels with abundant collagen deposition. There were few inflammatory cells and no rejection was found. CONCLUSION: This experiment showed that the acellular xenogenic dermal matrix, with fast neovascularization and low immunity, can be an ideal material of ocular implant and a good substitute for allogeneic sclera.

[Effects of magnetic field on MAPK signaling pathways of human retinal pigment epithelial cells bound with beads in vitro].

OBJECTIVE: To observe the changes of mitogen activated protein kinase (MAPK) signaling pathways of human retinal pigment epithelial cells( RPEs) bound with beads under stretch caused by the force from magnetic field in vitro. METHODS: Ferric oxide microparticles, coAted with collagen, were added to dishes containing substrate-attached RPEs. After incubation, the cell layer bound with beads was laid in a magnetic field, the cells were stretched by the magnetic force. The activation status of the extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinase (JNK), and p38 in RPEs was determined over a time course from 3 to 30 minutes with western-blot analysis. To examine the role of p38 kinase in the response to stretching, cells were grown for 30 minutes in the presence or absence of inhibitor of p38 (SB203580). The changes of the expression of active p38 kinase were observed with fluorescence staining. RESULTS: Total ERK, JNK, and p38 were detected in RPEs. Active ERK and p38 were detected but active JNK was not detected. Activation of ERK was unchanged during the time course. In contrast, p38 activation was barely detected in the normal cells, but this stress-activated protein kinase exhibited a robust activation after 5 minutes in the magnetic field. SB203580 blocked the p38 activation during stretch stimulation. The stretch stimulation also increased the fluorescence staining of active p38. CONCLUSION: A magnetic field can affect RPEs bound with beads. The effect may be partially through p38 signaling pathway.