As only limited evidence is available for potential benefits of n-3 PUFA supplementation in patients with peripheral arterial disease (PAD), we studied the effects of 4 g n-3 PUFA on endothelial function and inflammatory markers. Seventy patients with stable PAD classified as Rutherford stage 2 or 3 and good control of cardiovascular factors were randomised to receive either 4 g n-3 PUFA or placebo daily for 3 months in a double-blind fashion. Primary endpoint was endothelial function assessed by flow-mediated vasodilation (FMD). In addition, ankle–brachial index, maximum and pain-free walking distances were determined. Lipid parameters including the omega-3 index reflecting n-3 PUFA intake as well as pro-inflammatory, endothelial and platelet activation markers were measured over the same time interval. After 3 months of treatment with 4 g n-3 PUFA daily, a significant improvement of FMD was observed compared with placebo (n-3 PUFA, median Δ 3·7 (interquartile range (IQR) –1·8, 7·1) % v. placebo, Δ –0·5 (IQR –6·5, 3·0) %, P = 0·01 between the groups). After a 3-month washout period, this benefit was not sustained (n-3 PUFA, median Δ 0·6 (IQR –2·2, 5·6) % v. placebo, Δ –0·9 (IQR –6·6, 6·7) %, P = 0·20). In response to n-3 PUFA, an improvement of lipid parameters with a pronounced increase in the omega-3 index was seen. No changes were found for other parameters. In conclusion, in patients with PAD, 4 g/d n-3 PUFA improved cardiovascular risk in PAD patients, which needs testing in large-scale trials.

A number of plasma membrane receptor types originally thought to be specific to neurons have been found in other somatic cells. More surprisingly, the mammalian sperm and neuron appear to share many of these ‘neuronal’ receptors. The morphology, chromosome number, genomic activity, and functions of those two cell types are as unlike as any two cells in the body, but they both achieve their highly disparate goals with the aid of a number of the same receptors. Exocytosis in neurons and sperm is essential to the functions of these cells and is strongly influenced by similar receptors. ‘Neuronal’ receptor types in sperm may also play a role in the control of sperm motility (a function of course not shared by neurons).

This review will consider the evidence for the presence of sperm plasma membrane ‘neuronal’ receptors and for their significance to mammalian sperm function. The persuasiveness of the evidence varies depending on the receptor being considered, but there is strong experimental support for the presence and importance of a number of ‘neuronal’ receptors in sperm.

Angiotensin II, the effector peptide of the renin–angiotensin system (RAS), has potent growth factor properties in a variety of organs. In the retina, a complete RAS exists, with components residing in the vasculature, neurons and glia. There is increasing interest in a pathogenetic role for angiotensin II in ischaemic retinopathies such as diabetic retinopathy and retinopathy of prematurity. In these situations, the retinal RAS becomes activated and stimulates growth factors such as vascular endothelial growth factor, which contribute to vascular leakage, pericyte migration, angiogenesis and fibrosis. Blockade of the RAS, with either angiotensin-converting enzyme (ACE) inhibitors or antagonists selective for angiotensin type 1 (AT1) and angiotensin type 2 (AT2) receptors, attenuates many of the vascular abnormalities that develop in diabetic retinopathy and retinopathy of prematurity. Eagerly awaited are the findings of the Diabetic Retinopathy Candesartan Trial (DIRECT), evaluating the effects of AT1 receptor antagonism in patients with different stages of diabetic retinopathy. This review examines the role of the RAS in diabetic retinopathy and retinopathy of prematurity, and the potential of RAS blockade as a treatment strategy for these vision-threatening diseases.