Growth Of Lens Epithelial Cells Research Articles

Anterior capsule opacification and lens epithelial outgrowth on the intraocular lens surface after curettage

Purpose: To evaluate the long-term difference in lens epithelial cell (LEC) outgrowth on the anterior surface of a hydrogel intraocular lens (IOL) after curettage of the entire or one half of the circumference of the anterior capsule. Setting: Department of Ophthalmology, University of Vienna, Austria. Methods: Forty eyes with senile cataract only were randomly assigned to Group A, which had curettage of the entire anterior capsule, or Group B, which had curettage of the nasal half of the anterior capsule. Rentsch capsule curettes (Geuder) were used, a straight one for the nasal half and a bent model for the temporal half. One surgeon performed all standardized procedures with a temporal clear corneal incision, phacoemulsification, and in-the-bag implantation of a hydrogel IOL. Two years after surgery, the anterior surface of the IOL was examined by specular microscopy in a double-blinded fashion, and LEC outgrowth was graded semiquantitatively. Anterior capsule opacification (ACO) was also graded semiquantitatively. Results: In Group A, grade 2 ACO was observed in 53% of patients and grade 1 ACO in 47%. Similar results were achieved in Group B (59% and 41%, respectively). Two years after IOL implantation, the typically circumferential monolayer outgrowth of LECs on the hydrogel IOL surface was present in 80% in Group A and 60% in Group B. The ongrowth was less dense in the other IOLs; however, no significant differences between the groups were observed. Conclusions: Mechanical removal of residual LECs with a Rentsch capsule curette from the entire or from one half of the anterior capsule did not reduce LEC outgrowth 2 years after IOL implantation. Furthermore, the ACO grade was not significantly different. Lens epithelial cell proliferation in the germinative region and consecutive migration might be the cause of this outgrowth.

Inhibition of lens epithelial cell growth by induction of apoptosis: potential for prevention of posterior capsule opacification.

As a model of the cell proliferation occurring in posterior capsule opacification (PCO), lens epithelial cells (LEC) from human and rabbit capsulotomies, and a rabbit LEC line (N/N1003A) were grown in Dulbecco's Minimal Essential Media (MEM) with 10% fetal calf serum. LEC were exposed to the calcium ionophore, calcimycin, and viability was assessed by trypan blue staining, growth by 3H-thymidine incorporation and apoptosis by annexin/propidium iodide staining, calcein AM/ethidium bromide staining and DNA laddering. Human capsulotomy samples were similarly exposed to calcimycin, and apoptosis assayed by calcein AM/ethidium bromide staining. Calcimycin exposure induced apoptosis in both rabbit LEC cultures and human LEC, and changes leading to apoptosis could be detected within 30 minutes of calcimycin treatment. The decrease in viability and growth in human and rabbit LEC was dose-dependent. These data support the further evaluation of apoptosis induction as a possible treatment mechanism to prevent development of PCO following primary cataract surgery in humans.

Effect of intraocular lens haptic compressibility on the posterior lens capsule after cataract surgery

Purpose: To evaluate the effect of intraocular lens (IOL) haptic compressibility on the posterior capsule after cataract surgery. Setting: Teaching hospital, London, United Kingdom. Methods: In this randomized prospective study, 60 patients had standardized phacoemulsification with in-the-bag placement of a poly(methyl methacrylate) (PMMA) (Storz P497UV) or hydrogel (Storz Hydroview H60M) IOL. Both IOLs had PMMA haptics of identical configuration and length. The IOL haptic compressibility was measured in air and then during incubation in saline at 37°C over 1 month. Digital retroillumination imaging was performed 1, 7, 28, 90, 180, 360, and 720 days postoperatively. The presence and duration of postoperative capsule folds were recorded and correlated with the haptic compressibility measurements, lens epithelial cell (LEC) growth patterns on the posterior capsule at 6 months, and the extent of posterior capsule opacification. Results: On the first postoperative day, 21 patients (88%) in the Hydroview group had posterior capsule folds that persisted in 12 patients (50%) for 2 years. Nineteen patients (68%) in the PMMA group had folds at day 1 ( P = .01), with 1 patient (3%) still having folds at 1 month ( P = .0002) and no patient having folds at 3 months. At 6 months, 11 patients (46%) in the Hydroview group and no patient in the PMMA group had LEC growth in the direction of the folds. The PMMA IOLs showed a greater decrease in haptic compressibility during incubation. Conclusions: Haptic compressibility should be an important consideration in IOL design. The results suggest that to avoid posterior capsule folds, the compressibility should be less than 2.5 mN.

The Effect of Polymethylmethacrylate and AcrySof Intraocular Lenses on the Posterior Capsule in Patients with a Large Capsulorrhexis

Purpose: We have previously shown that patients who have a capsulorrhexis larger than the diameter of a polymethylmethacrylate (PMMA) intraocular lens (IOL) rapidly develop increased posterior capsule opacification (PCO), in effect, producing an example of enhanced PCO. This study focuses on the influence of AcrySof IOLs on this process. Methods: Phacoemulsification was performed on two groups of patients. The first consisted of 38 patients with a large capsulorrhexis of 6–7 mm who received a 5.5-mm PMMA IOL. The second group of 32 patients had identical surgery and a 5.5-mm MA30 AcrySof IOL was implanted. On days 1,14, 28, 90, 180, and 360, high resolution digitized retroillumination images were taken of the posterior capsule. The PCO area was measured by image analysis at 90, 180, and 360 days. Wrinkling of the posterior capsule was determined at 90 days, and the progression or regression of lens epithelial cell (LEC) proliferation was established by examination of serial images at 28 and 180 days. Results: At 90 days, 79% of the patients with PMMA IOLs had moderate to severe wrinkling of the posterior capsule, whereas the patients with AcrySof IOLs had none ( P < .001). The percentage of PCO area was 69% for the PMMA IOLs and 24% for the AcrySof IOL group at 360 days ( P < .0001). In the PMMA group, LEC progression occurred in 77%, LEC growth was stable in 15%, and LEC regression occurred in only 8%, compared to 69% of patients with AcrySof IOLs ( P < .0001). Conclusions: In patients with a rhexis larger than the IOL, AcrySof IOLs potentially can prevent capsular wrinkling and cause less PCO than a PMMA IOL with a similar rhexis size. The LEC regression occurs with AcrySof between 28 and 180 days. The reasons for this are discussed.

Lens epithelial cell outgrowth on 3 types of intraocular lenses

Purpose To compare the outgrowth of lens epithelial cells (LECs) on 3 types of intraocular lenses (IOLs) to determine the influence of lens material and lens design (optic edge) on this phenomenon. Setting Department of Ophthalmology, University of Vienna, Medical School, Vienna, Austria. Method Ninety eyes scheduled for cataract surgery were included in a prospective comparative study. A standardized surgical procedure was performed by 1 experienced surgeon. Patients received 1 of 3 types of posterior chamber IOLs of similar design with a 6.0 mm optic and poly(methyl methacrylate) haptic: AcrySof® (Alcon), HydroView™ (Bausch & Lomb), or Sensar™ (Allergan). Each IOL type was implanted in 30 eyes. Postoperative biomicroscopic examinations were performed 1, 3, 7, 30, 90, and 180 days and 1 year after surgery. Lens epithelial cells in each quadrant of the anterior lens surface were subjectively graded. The product with the highest density and the number of quadrants with this density were used to measure LEC outgrowth. Results Statistically significant differences ( P < .05) were seen between the hydrophilic IOL and the 2 hydrophobic lenses from day 30 until the final examination. The HydroView lens had a higher number of LECs on its anterior surface than the AcrySof or Sensar IOL. There were no statistically significant differences between the 2 acrylic IOLs at any measurement. Conclusion The findings suggest that lens surface properties have a greater influence on LEC outgrowth than lens design (ie, sharp optic edge).

Lens Epithelium-Derived Growth Factor: Effects on Growth and Survival of Lens Epithelial Cells, Keratinocytes, and Fibroblasts

We isolated a clone encoding a protein from a human lens epithelial cell (LEC) cDNA library with antibody (Ab) from a cataract patient and named it “lens epithelium-derived growth factor” (LEDGF). LEDGF is found to be identical to p75, a coactivator of both transcription (1) and pre-mRNA splicing (2). In serum-free medium LEDGF stimulated growth of LECs, cos7 cells, skin fibroblasts, and keratinocytes, and prolonged cell survival. Without LEDGF, the aforementioned cells did not survive. Also in serum-free medium, Ab to LEDGF neutralizing LEDGF blocked cell growth and caused cell death. Thus, LEDGF, a regulatory factor, may play an important role for growth and survival of a wide range of cell types.

Effects of intermittent UVA exposure on cultured lens epithelial cells

Purpose. This paper addresses the question of whether a single non-lethal dose of UVA radiation or the same dose divided three daily one-third doses have like or unlike effects on the growth and the catalase activity of cultured rabbit epithelial (RLE) and immortalized human epithelial (HLE) cells. Methods. Non-confluent cultured RLE and HLE cells were used to study the effects of UVA radiation on their growth. The effects of three doses of 3 J/cm 2 given one day apart on cell growth (i.e. live cell number) over a three day period were compared with those of a single 9 J/cm 2 exposure. Estimation of live cell numbers was done 24 hrs after each exposure by counting trypan blue exclusive cells using a hemocytometer. Confluent cultures of RLE cells were used to study the effects of UVA radiation on their catalase activity. The effects of three doses of 1.25 J/cm 2 each given one day apart on catalase activity (breakdown of H 2 O 2 measured spectro-photometrically at 240 nm) were compared with that of a single 3.75 J/cm 2 exposure. Results. A single 9 J/cm 2 dose of UVA reduced the cell growth to only 10% of controls after 24 hrs. By three days after a single 9 J/cm 2 exposure, the number of live cells was only 70% of controls. Three intermittent exposures of 3 J/cm 2 each for three consecutive days reduced the cell number to 76% of controls. Similar results were obtained for HLE cells. Little if any recovery of cell numbers occurred after three intermittent exposures. A single dose of 3.7 J/cm 2 reduced RLE catalase activity to 20% of controls by one day. By three days after exposure, catalase activity returned to 90% of controls. After three intermittent exposures to 1.25 J/cm 2 each, over three days, RLE catalase activity was reduced to 75% of the controls. There appeared to be no recovery within two additional days. Conclusions. While single below lethal doses of UVA allow no recovery of RLE or HLE cell growth, partial recovery does occur after several daily intermittent exposures. Recovery of the catalase activity by RLE cells does occur after single sub lethal exposures, but intermittent exposures allow no recovery. The recovery of lens epithelial cell growth and catalase activity from UVA damage varies with the exposure regimen.

Cell biology of posterior capsular opacification

Posterior capsular opacification (PCO), a major complication of modern cataract surgery, necessitates further surgical intervention in 10-50% of patients. PCO results from the growth and transdifferentiation of lens epithelial cells left on the anterior capsule at the time of cataract surgery. These cells proliferate to form monolayers on the capsular surfaces, and such monolayers continue to line the anterior capsule leaflet many years after surgery. Some cells, however, differentiate or undergo a transition to another cell type, and these processes greatly contribute to PCO. Equatorial differentiation of cells to fibre-like structures leads to Soemmerring's ring formation and peripheral thickening of the capsular bag. Closer to the rhexis, cell swelling can result in globular Elschnig's pearls, which may occlude the visual axis. Cells at the rhexis edge and those in the space around the optic appear to undergo epithelial-mesenchymal transition. The resulting cells are fibroblastic in morphology, express the smooth muscle isoform of actin and secrete extracellular matrix containing proteins not normally present in the lens.

Diclofenac sodium and cyclosporin A inhibit human lens epithelial cell proliferation in culture.

To investigate the effect of diclofenac sodium salt and cyclosporin A (CsA) on human lens epithelial cell (HLEC) growth in culture. Cultures of HLEC were obtained from anterior capsules from extracapsular cataract surgery. Third-passage cells were seeded in 96-well plates in 0.1 ml culture medium. Cytotoxicity was estimated by the tetrazolium test in confluent monolayers after 24 h exposure to a wide range of concentrations of diclofenac and CsA. The effect of subcytotoxic concentrations of diclofenac and CsA on HLEC proliferation in subconfluent cultures was evaluated after 24 and 72 h of exposure. To investigate the relationship between PGE2 synthesis and the inhibitory effect of these drugs, after 24 h of exposure to diclofenac and CsA the production of PGE2 was measured by radioimmunoassay. We also tested the effect of exogenous PGE2 addition to diclofenac 72-h-treated cultures. Diclofenac and CsA (at concentrations > or = 65 microM and > or = 2.5 microM, respectively) inhibited the proliferation of subconfluent cultures of HLEC in a dose-dependent fashion. Diclofenac inhibits PGE2 synthesis, while CsA at high doses stimulates PGE2 synthesis of cultured HLEC. Exogenous PGE2 addition reversed in part the inhibitory effect of diclofenac. Diclofenac and CsA at appropriate doses are effective in inhibiting cultured HLEC proliferation. This could be of interest to prevent posterior capsule opacification. Further in vivo experimental studies seem worthwhile.

Feline ocular epithelial response to growth factors in vitro

Abstract Objective To examine the proliferative abilities of growth factors known to participate in wound healing on feline lens, iris pigment, ciliary, and retinal pigment epithelium cultured in vitro. Animals 8 clinically normal cats. Procedure Iris pigment, lens, ciliary, and retinal pigment epithelia of normal eyes of cats were isolated and cultured. Morphologic characteristics of primary cell cultures were studied by light and electron microscopy. Subcultures of epithelial cells were exposed to media supplemented with 0.5% fetal bovine serum plus various combinations of insulin and/or growth factors, including transforming growth factor-α, epidermal growth factor, acidic fibroblast growth factor, and basic fibroblast growth factor. Growth promoting effects were evaluated by counting with an electronic cell counter. Results Cells retained many of the morphologic characteristics of in vivo cells. Cell proliferation assays indicated that transforming growth factor-α stimulated lens and ciliary epithelial cell growth, and epidermal growth factor enhanced lens and iris pigment epithelial cell growth. Acidic fibroblast growth factor had proliferative effects on lens, iris pigment, and ciliary epithelium. Basic fibroblast growth factor was the most potent stimulator of all mitogens used, and caused substantial proliferation in all cell types. Insulin alone stimulated lens and ciliary epithelial proliferation but, combined with other growth factors, had a synergistic effect with those causing cell proliferation, except acidic fibroblast growth factor with iris pigment epithelium. Conclusion Morphologic studies support the argument that pigment-producing cells are involved in feline ocular sarcoma. Growth factor studies indicated that ciliary epithelium has the most profound proliferative effect of all growth factors used. These data may help guide future studies in determining the cell of origin for feline ocular sarcoma. (Am J Vet Res 1996;57:1748–1752)

Lens epithelial cell outgrowth and matrix formation on intraocular lenses in rabbit eyes

Purpose: To evaluate the presence and distribution of lens epithelial cells (LECs) and extracellular matrix on intraocular lenses (IOLs) implanted in the capsular bag in rabbit eyes.Setting: Department of Ophthalmology, Wakayama Medical College, Wakayama, Japan.Methods: Five adult albino rabbits had phacoemulsification and IOL implantation in both eyes. Two or 11 months later, the animals were killed by intravenous pentobarbital. The IOLs were removed and observed under scanning and transmission electron microscopy.Results: In addition to the macrophages and giant cells on the IOLs, all eyes had a monolayer of flattened cells growing out from the residual anterior lens capsule and a fibrous meshwork of extracellular matrix. Unlike those of a macrophagic origin, these cells had no central cytoplasmic elevation of nuclei and few cell surface microvilli and were considered to be proliferating LECs.Conclusion: Lens epithelial cells are involved in the eye's cellular reaction to IOLs and in the formation of extracellular matrix on IOLs. Further study of LEC behavior on IOLs should be done to improve IOL biocompatibility.

Regulation of lens cell growth and polarity by an embryo-specific growth factor and by inhibitors of lens cell proliferation and differentiation

We used a double-label method, which monitors the rate at which cells enter S-phase of the cell cycle, to identify factors that control the growth of chicken embryo lens epithelial cells in vivo. With this assay, we identified a mitogen for lens epithelial cells in the anterior segment of the embryonic eye. When the anterior chamber was opened briefly, by tearing the cornea or displacing the lens, the growth-promoting activity was lost. None of the purified growth factors tested replaced this growth activity, including EGF, bFGF, PDGF, IGF-1, IGF-2, TGF beta and mixtures of these factors. However, chicken embryo serum or plasma did cause chicken embryo lens epithelial cells to progress through the cell cycle. The activity in serum was destroyed by heat and protease treatment. It was most active in serum from 10-day embryos, decreased with subsequent development and was undetectable from 2 days after hatching through adulthood. When embryo serum or plasma was mixed with vitreous humor or IGF-1, agents that induce lens fiber cell formation, cell elongation was prevented. In contrast to the mitogenic activity in serum, this inhibitor of differentiation was insensitive to trypsin treatment. We also identified an activity in vitreous humor that inhibited the growth-promoting agent in embryo serum. Plasma proteins readily enter the anterior chamber of the eye of chicken embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

Biphasic effect of the mitotoxin bFGF-saporin on bovine lens epithelial cell growth: effect of cell density and extracellular matrix.

We have studied the effect of a specific FGF receptor suicide antagonist on the growth of bovine epithelial cells (BEL cells) in culture. This basic fibroblast growth factor-saporin conjugate (bFGF-SAP) has a biphasic effect on bovine lens epithelial cells (BEL cells). Whereas 0.01 nM and 0.1 nM bFGF-SAP stimulate BEL cells proliferation, 1 nM and 10 nM bFGF-SAP have the predicted toxic effects on BEL cell growth. The toxicity of bFGF-SAP is observed 2 to 3 days after the initial treatment and depends on cell density. Accordingly, the sensitivity of confluent cells to bFGF-SAP is reduced compared to sparse cells. A time course analysis reveals that bFGF-SAP is effective after a short exposure to cells and that its effects are not increased with longer treatments. Cell growth on bFGF-SAP pretreated extracellular matrix (ECM) or posterior lens capsule (PLC) is also affected. Basic FGF-SAP has been shown to bind to the extracellular material, allowing a modulation of lens cells migration and survival by a single treatment in vitro. This finding raises the possibility of its use in vivo to prevent capsules invasion by lens cells after cataract surgery.

Effect of freezing on lens epithelial cell growth

The effect of freezing on the growth of rat lens epithelial cells was studied in vitro. We found that 80% of the lens epithelial cells died after freezing at −45°C for two hours and that the surviving cells could grow with the addition of growth factors or when placed on a sheet of type 4 collagen, but not when placed on a plain plastic culture dish. These results suggest that the surviving cells are at the Go phase of the cell cycle and that type 4 collagen or growth factors can initiate cell division.

In Vitro Inhibition of Lens Epithelial Cell Proliferation and Migration

Delayed opacification of the posterior capsule is the most common cause of decreased visual acuity after extracapsular cataract extraction. In humans, this has been shown to result from migration and possibly proliferation of residual lens epithelial cells onto the central posterior capsule. We studied a group of pharmacologic agents to determine their ability to inhibit lens epithelial cell proliferation and migration in vitro. A drug capable of inhibiting lens epithelial cell growth and/or migration, if free of unacceptable toxic effects on other cell populations, might be used to prevent lens capsule opacification. Anti-proliferative activity was exhibited by several agents, with 50% inhibition of growth occurring at the following concentrations: 5-fluorouracil, 30 micrograms/ml; daunomycin, 10 ng/ml; colchicine, 15 ng/ml; doxorubicin, 5 ng/ml; dexamethasone, 100 micrograms/ml; and cytosine arabinoside, 100 ng/ml. Colchicine inhibited lens epithelial cell migration by 50% at 20 ng/ml.

The effects of steroids on the human lens epithelium.

A study of anterior capsules from cataractous lenses revealed that there are marked abnormalities in epithelial structure associated with cataract. In certain cases a distinctive reticulated pattern was observed in whole mounts of the anterior capsule and of these a higher number than expected were from patients receiving steroid medication. In tissue culture experiments it was found that the presence of steroids in the growth medium (10 microM prednisolone) adversely affected the growth of human lens epithelial cells. These observations are consistent with the hypothesis that steroid-induced cataracts are the result of effects on anterior lens epithelial cell function.

Plasma factors involved in the in vitro control of proliferation of bovine lens cells grown in defined medium. Effect of fibroblast growth factor on cell longevity

Experimental conditions have been defined that allow cultured bovine lens epithelial cells to grow in the complete absence of serum. Early-passage low density lens epithelial cell cultures seeded in absence of serum on extracellular matrix- (ECM-)coated dishes proliferate actively when exposed to Dulbecco's modified Eagle's medium (DME) supplemented with high-density lipoprotein (HDL, 250 μ g protein/ml) and transferrin (10 μ g/ml). Late-passage cultures required, in addition to HDL and transferrin, the presence of insulin (2·5 μ g/ml) and fibroblast growth factor (FGF, 100 ng/ml). Omission of any of these components results, in late-passage cultures, in a slower growth-rate and in a lower final cell density. Lens epithelial cell cultures seeded on plastic dishes grow very poorly when exposed to similar conditions. The life spans of lens epithelial cell cultures maintained on plastic vs. fibronectin or ECM-coated dishes and exposed to serum-free vs. serum-supplemented medium have been compared. While cultures maintained on ECM and exposed to serum-supplemented medium had a life span of over 190 population doublings, similar cultures maintained on plastic had a life span of 59 population doublings. When lens epithelial cells were maintained on ECM and exposed to medium supplemented with optimal concentrations of HDL, transferrin, and insulin, cultures maintained in the absence of FGF underwent 28 population doublings and over 100 in its presence. Although fibronectin-coated dishes did support the long-term growth of lens epithelial cells exposed to transferrin-HDL and insulin, the life span of such cultures was shorter (13 population doublings) than that of similar cultures maintained on ECM-coated dishes. Addition of FGF to the medium increased the life span of such cultures to 38 population doublings. The enhancing effect of ECM and FGF on lens epithelial cell growth and culture longevity clearly illustrates the importance of the cell substrate and growth factors in the control of proliferation of these cells.

Anchorage-independent growth of normal calf lens epithelial cells and effect of SV40 transformation on their growth properties.

Calf lens epithelial cells cultured in vitro show growth properties usually associated with virally transformed fibroblasts. The lens cells are anchorage independent, forming colonies in agar, and show a low requirement for added mitogens. In dense culture they form multilayers and maintain a constant cell number by proliferation and shedding. Strains of lens cells transformed by SV40 virus have been obtained that show similar growth properties to the normal lens epithelium. The major effect of SV40 transformation is to increase the growth rate, final cell density and in vitro life-span of the lens cells and to inhibit the increase in size that occurs after 2-3 weeks of culturing the untransformed cells.

Donor age influences the growth of rabbit lens epithelial cells in vitro

Experiments were designed to optimize the conditions required for the establishment of cell lines from individual rabbit and human lenses. The influence of donor age and the response of the epithelia to various media, sera, substrata and growth factors were determined. Epithelial cells were obtained from 4–6-day-, 3-, 5-, 8-, 10-week- and 4-months- to 4-yr-old rabbits. Cell lines from animals aged 4 months or older were maintained in culture for over 2 yr, had a population doubling time of ca. 2.5 days, required serum for growth, and contained polypeptides that comigrated with and had an apparent molecular weight of known lens crystallins. Explants or enzymatically dissociated cells from 4–6-day-, 3-or 5-week-old donors exhibited little mitosis. This limited growth occurred in cells cultured in Eagle's MEM, BME. Dulbecco's modified MEM, medium 199, RPMI-1640, Ham's F-14, Leibovitz's L-15, KEI-4 or in a modified Ca 2+-free MEM, supplemented with heat-inactivated rabbit or bovine sera or in these sera-containing-media supplemented with growth factors. Cells from the 4–6-day-olds migrated from the explant, synthesized DNA, enlarged, but did not show a marked increase in cell number. Analysis of video tapes indicated that the outgrowth from the explants of 4–6-day-olds was due solely to cell migration. Under similar culture conditions fibroblasts from 4–6-day-old rabbits or lens epithelia from rabbits 4 months or older were capable of generating continuous cell lines. Under like culture conditions, lens epithelia from humans aged 30–89 yr underwent a maximum of only three subcultures, enlarged and did not divide. Human lens cells have been maintained in a viable non-dividing condition for 1 yr. Cell lines possessing lens-specific proteins could be obtained from 4–6-day-old or 3-week-old rabbits if the cells were cultured in MEM containing non-heat inactivated rabbit serum. Clearly, the growth requirements of lens epithelial cells from younger rabbits can be markedly different from those of their older counterparts.

A Study of Human Senile Cataract: Growth and Differentiation of Lens Epithelial Cells in in vitro culture

Epithelial cells of human senile cataractous lenses from aged patients (over 60) were cultured <i>in vitro</i>. They began to grow from the 4th to 6th day of culture and formed typical epithelial cell sheets. The lentoid identified by immunochemical methods as a mass of lens fibers were found to develop at the terminal period of the primary culture. From the secondary passage of the culture, the growth potential of the cells decayed rapidly. It was also demonstrated clearly that the senile cataractous lenses still contained a small number of active epithelial cells exhibiting rather high growth and differentiation potentials, No signficant relationships between activities of epithelial cells and the condition of cataract have been observed so far.