Age-related macular degeneration (AMD) is a major cause of blindness in the United States. AMD can be categorized into an atrophic (dry) form and a neovascular (wet, exudative) form. The atrophic form involves alterations of pigment distribution, loss of RPE cells and photoreceptors and diminished retinal function due to an overall atrophy of the cells. The neovascular AMD involves proliferation of abnormal choroidal vessels, which penetrate the Bruch's membrane and RPE layer into the subretinal space, thereby forming extensive clots and/or scars. Both environmental and genetic factors are suspected to play a role in AMD. Despite extensive genetic screening of candidate genes only two associations have been identified with AMD (Adenosine triphosphate (ATP)-binding cassette rim (ABCR) protein and apolipoprotein E gene-ApoE). The ABCR protein is retinal specific and accounts for only 3% of AMD cases. ApoE is not specific to the retina, and has been more intriguingly associated with Alzheimer's, another disease of age. The most consistent major risk factor in AMD is age. Our studies on the ACE gene show an association of protection with an Alu element insert, which might be affecting the level of the ACE gene. The ApoE 4 allele and the ACE Alu+/+ genotype have both been shown to be a risk for Alzheimer's and protective for AMD. Given these recent genetic associations, we should examine possible common pathways in diseases of age and their interaction with human genetic polymorphisms.

Our recent morphological studies showed that basement membranes isolated from renal tubules tended to collapse and form folded sheets while glomerular basement membranes were more resilient. In an effort to study the shapes of various isolated basement membranes in undissociated tissues, a method was developed to remove all cellular elements and leave the extracellular matrix and associated basement membranes intact. Accordingly, transplant quality human kidneys were harvested, perfused with Collin’s medium and transported to the laboratory on ice. The renal cortex was then peeled away by blunt dissection, further minced to 2 mm³ and placed in 1 mM EDTA (with gentle intermittent stirring) for 72 h at 4°C. Solubilization of cellular materials was carried out by successive washings with 3% Triton X-100, 0.025% DNAse and 1–4% sodium deoxycholate (all with gentle stirring or shaking at 22 °C). Each solution contained 0.1% sodium azide. At the level of fine structure, glomerular, tubular, Bowman’s capsular and peritubular capillary basement membranes all maintained their respective shapes and did not collapse. Glomerular basement membrane was particularly striking in this regard and exhibited an open, lobulated form that closely resembled its in vivo histoarchitecture. Moreover, when the acellular tissue blocks were prepared for scanning electron microscopic observation, the glomerular basement membranes exposed at the surface of the block showed a remarkable structural rigidity. These basement membranes were free-standing, convoluted electron-dense sheets, continuous with highly folded central mesangial regions. It seems significant that glomerular basement membranes maintain their in vivo conformation irrespective of the presence of other extracellular matrix components while removal of these materials by organ subfractionation results in folding and general shapelessness of tubular basement membrane. It is possible that in addition to its unique role in filtration, glomerular basement membrane may also serve to preserve glomerular shape, regardless of changing cell populations or alterations in hydrostatic pressures.

Aim:To explore the molecular pathophysiology that might explain the epidemiologic association between cigarette smoke and age-related macular degeneration (AMD) by examining the effects of hydroquinone (HQ), a toxic compound present in high concentration in cigarette smoke-related tar, on human retinal pigment epithelial cells (ARPE-19), rat retinal neurosensory cells (R-28), and human microvascular endothelial cells (HMVEC).Materials and Methods:ARPE-19, R-28, and HMVEC were treated for 24 h with four different concentrations of HQ (500 μM, 200 μM, 100 μM, 50 μM). Cell viability, caspase-3/7 activation, DNA laddering patterns, and lactate dehydrogenase (LDH) levels were analyzed.Results:At 50 μM HQ, R-28 cells showed a significant decrease in cell viability compared with the dimethyl sulfoxide (DMSO)-treated controls. At the 100–500 μM concentrations, all three cell lines showed significant cell death (P < 0.001). In the ARPE-19, R-28, and HMVEC cultures, the caspase-3/7 activities were not increased at any of the HQ concentration.Conclusion:Our findings suggest that the mechanism of cell death in all three cell lines was through non-apoptotic pathway. In addition, neuroretinal R-28 cells were more sensitive to HQ than the ARPE-19 and HMVEC cultures.

The severity and incidence of spinal lesions were manipulated in a line of chickens susceptible to scoliosis by varying their dietary intake of copper. A decrease in expression of the lesion was related to increased intake of copper. The change in expression, however, appeared to be related only indirectly to the defects in collagen cross-linking, maturation, and deposition known to be associated with dietary copper deficiency. Thus, a dietary constituent in the range of normal intakes may act as an environmental factor in the expression of scoliosis.

The pathogenesis of many corneal diseases involves alteration in endothelium and subjacent Descemet’s membrane. A common manifestation of these disorders is the appearance of a retrocorneal fibrous membrane (RCM) composed of dissociated endothelial cells interposed between layers of Descemet’s membrane-like materials. The stimulus for the endothelium to lose its epithelioid characteristics and assume this more fibroblastic behavior is unknown. In the present study we describe tissue culture conditions which stimulate isolated corneal endothelial cells to undergo a transition similar to that seen in RCM formation. Accordingly, a monolayer of hexagonal endothelial cells become multilayered metaplastic cells and produce abundant Descemet’s membrane-like material. Cells were isolated by enzyme digestion and modification of thiol groups to yield single or small 2- to 3-cell aggregates which could be evenly dispersed on plastic tissue culture dishes. Contaminating stromal fibroblasts were not present in these preparations as verified morphologically. Cultures were confluent within 5–7 days after plating and at 28 days of incubation, cultures displayed features similar to regenerating rabbit endothelium. These included loss of contact inhibition leading to multilayering of cells, intracytoplasmic densities and extracellular matrix (ECM) which accumulated not only between the basal layer of cells and plastic substratum but also in the cellular interstices. The fibrillar and amorphous components of this ECM accumulated in thin layers and were ultrastructurally similar to the anterior banded and posterior unbanded portions of Descemet’s membrane, respectively. This in vitro lamination of cells and their ECM is highly reminiscent of the RCM accompanying various corneal diseases. Therefore, our in vitro system, leading to the formation of multilaminar corneal endothelial cells, provides an advantageous experimental model for studies of cellular activity leading to RCM formation.