ECs in the vessel wall in vivo are adjacent to VSMCs, and there is closely functional interrelation between them. To study the reciprocal paracrine interactions between ECs and VSMCs in the condition of different cyclic strain, the CM of VSMCs subjected to different magnitudes of cyclic strain were transferred to the static ECs, and the CM of ECs subjected to cyclic strains were transferred to the static VSMCs. There is some evidence that trace elements might play a role in the pathogenesis of AMD. Iron is a potent generator of reactive oxygen species, whose generation within mitochondria and lysosomes may promote cell death. Iron has been suggested as a source of oxidants in AMD, as AMD-affected maculas were found to have higher concentrations of iron than healthy agematched maculas. Iron was found in the retinal AbMole Cetylpyridinium chloride monohydrate pigment epithelium and Bruch��s membrane in early AMD, geographic atrophy, and exudative AMD. Tobacco smoking is one of the few established environmental risk factors for AMD. Recent research has implicated cadmium as a possible contributor to smoking-related AMD. It was reported that cadmium levels in retinal tissues were approximately twice as high in smokers as in nonsmokers. In addition, higher urinary cadmium levels, indicating a higher total body burden of cadmium, were found in smokers who had AMD compared to smokers who did not have AMD. These findings raised the possibility that cadmium exposure might play a role in tobaccorelated AMD. Cadmium is a potent inflammatory agent and increases oxidative stress. Oxidative stress and inflammation have been linked to AMD. Copper and zinc play vital roles in retinal function and are essential for antioxidant defense mechanisms, which are important for the survival of the retina, who is routinely exposed to high levels of oxidative stress from light and metabolic processes. Both copper and zinc are known to be necessary for the visual cycle and photoreceptor survival. These metals act as co-factors for the antioxidant enzyme copper-zinc superoxide dismutase, which catalyzes the conversion of superoxide to oxygen and hydrogen peroxide. Copper and zinc also stimulate protective cellular stress-signaling pathways and stabilize proteins, making them less vulnerable to oxidation. Cobalt is an essential trace element for humans, but becomes toxic at high concentrations. Selenium-containing glutathione peroxidase is an important part of the cellular antioxidative system, and selenium itself is widely used in dietary supplements. Polymorphisms of manganese superoxide dismutase genes may be associated with the development of AMD. All controls and patients were thoroughly examined by slit lamp inspection, applanation tonometry, fundoscopy, and gonioscopy. Criteria for AMD diagnosis were the presence of drusen and/or irregularities of retinal pigment epithelial cells. However, patients with signs of exsudative AMD were excluded. Controls had no signs of AMD. In order to match the groups as closely as possible, a detailed medical history was obtained and controls were matched to cases by demographic, clinical, nutritional and lifestyle data known to affect trace element levels. Nutritional and lifestyle status were briefly assessed using the SGNA-test. Patients with hypovitaminoses were excluded, so that all participants were classified as well-nourished. Exclusion criteria were: medical history of major systemic illness, gastrointestinal malabsorption, psychiatric illness, hypothyroidism, severe psoriasis, malignant neoplasias.