function, we carried out gene transfer studies using a plasmid in which Vcsa1 was expressed from a cytomegalovirus promoter (pVAXVcsa1). This plasmid was injected intracorporally into old rats, and the effect on physiology of corporal tissue was analysed by intracorporal/blood pressure (ICP/BP) measurement and histological analysis, and compared with the effects of a positive control plasmid (pVAX-hSlo, which we previously reported to restore erectile function in diabetic and ageing rats) and a negative control plasmid (pVAX). RESULTSIn each rat model of ED there was a significant down-regulation of the Vcsa1 transcript of at least 10-fold in corporal tissue. Remarkably, intracorporal injection with 80 µ g pVAX-Vcsa1 caused priapism, as indicated by visible prolonged erection, histological appearance, and elevated resting ICP/BP. Lower doses of pVAX-Vcsa1 (5 and 25 µ g) increased ICP/BP over that in untreated controls. CONCLUSIONThese results show that Vcsa1 has a role in erectile function and might be a molecular marker for organic ED. The role of Vcsa1 in erectile function suggests that it could represent a novel therapeutic target for treating ED.

Intracorporal injection of plasmids encoding opiorphins into retired breeder rats can result in animals developing a priapic-like condition. Microarray analysis demonstrated that following intracorporal gene transfer of plasmids expressing opiorphins the most significantly upregulated gene in corporal tissue was the ornithine decarboxylase gene (ODC). Quantitative RT-PCR confirmed the upregulation of ODC, as well as other genes involved in polyamine synthesis, such as arginase-I and -II, polyamine oxidase, spermidine synthase, spermidine acetyltransferase (SAT), and S-adenosylmethionine decarboxylase. Western blot analysis demonstrated upregulation of arginase-I and -II, ODC, and SAT at the protein level. Levels of the polyamine putrescine were upregulated in animals treated with opiorphin-expressing plasmids compared with controls. A direct role for the upregulation of polyamine synthesis in the development of the priapic-like condition was supported by the observation that the ODC inhibitor 1,3-diaminopropane, when added to the drinking water of animals treated with plasmids expressing opiorphins, prevented experimental priapism. We also demonstrate that in sickle cell mice, another model of priapism, there is increased expression of the mouse opiorphin homologue in corporal tissue compared with the background strain at a life stage prior to evidence of priapism. At a life stage when there is onset of priapism, there is increased expression of the enzymes involved in polyamine synthesis (ODC and arginase-I and -II). Our results suggest that the upregulation of enzymes involved in the polyamine synthetic pathway may play a role in the development of experimental priapism and represent a target for the prevention of priapism.

Purpose To elucidate the molecular pathogenesis of age-related macular degeneration (AMD) and interpretation of fundus autofluorescence (AF) imaging, we identified spectral AF characteristics of drusen and retinal pigment epithelium (RPE) in donor eyes with AMD. Methods Macular RPE/Bruch’s membrane (BrM) flat mounts were prepared from 5 donor eyes with AMD. In 12 locations (1–3/eye), hyperspectral AF images in 10-nm-wavelength steps were acquired at 2 excitation wavelengths (λex 436 nm, 480 nm). A non-negative tensor factorization algorithm was used to recover 5 abundant emission spectra and their corresponding spatial localizations. Results At λex 436 nm, we consistently localized a novel spectrum (SDr) with a peak emission near 510 nm in drusen and sub-RPE deposits. Abundant emission spectra seen previously (S0 in BrM and S1, S2, and S3 in RPE lipofuscin/melanolipofuscin (L/ML), respectively), also appeared in AMD eyes, with the same shapes and peak wavelengths as in normal tissue. L/ML spectra localizations in AMD eyes varied widely in their overlap with drusen, ranging from none to complete. Conclusions An emission spectrum peaking at ~510 nm (λex 436 nm) appears to be sensitive and specific for drusen and sub-RPE deposits. One or more abundant spectra from RPE organelles exhibit characteristic relationships with drusen.