Elements and organic substances in epiretinal proliferative tissue excised during vitreous surgery: analysis by time-of-flight secondary-ion mass spectrometry

We examined with time-of-flight secondary-ion mass spectrometry (TOF-SIMS) various substances in vitreous proliferative tissues excised from patients with proliferative diabetic retinopathy or proliferative vitreoretinopathy. Amounts of elements, vitamins and fatty acids were measured with TOF-SIMS and then the average ratio of the count of spattered ions of each element and organic substance to the total count of spattered ions was calculated. The average ratios of Fe, Ca, Al, Zn and Cu ion counts to the total count of spattered ions were significantly larger in proliferative diabetic retinopathy than in proliferative vitreoretinopathy. The average ratios of each of vitamin A fragment-1 and palmitic acid ion counts to the total count of spattered ions were significantly larger in proliferative diabetic retinopathy than in proliferative vitreoretinopathy. The fact that diabetic and non-diabetic preretinal proliferative tissues contain organic substances suggests that these proliferative tissues are derived from the retina, especially the deep retina, probably the photoreceptor cell and/or retinal pigment epithelium. The presence of Zn and Cu also suggest the same process. Diabetic proliferative tissues rich in organic substances are thought to grow more than do non-diabetic tissues, because vitamins A and E, and fatty acids are necessary for the maintenance of cell structure and the proliferation of tissue. Analysis of biological specimens by TOF-SIMS is expected to provide valuable information.