Pharmacological Inhibition of Nicotinamide Phosphoribosyltransferase/Visfatin Enzymatic Activity Identifies a New Inflammatory Pathway Linked to NAD

Nicotinamide phosphoribosyltransferase (NAMPT), also known as visfatin, is the rate-limiting enzyme in the salvage pathway of NAD biosynthesis from nicotinamide. Since its expression is upregulated during inflammation, NAMPT represents a novel clinical biomarker in acute lung injury, rheumatoid arthritis, and Crohn's disease. However, its role in disease progression remains unknown. We report here that NAMPT is a key player in inflammatory arthritis. Increased expression of NAMPT was confirmed in mice with collagen-induced arthritis, both in serum and in the arthritic paw. Importantly, a specific competitive inhibitor of NAMPT effectively reduced arthritis severity with comparable activity to etanercept, and decreased pro-inflammatory cytokine secretion in affected joints. Moreover, NAMPT inhibition reduced intracellular NAD concentration in inflammatory cells and circulating TNFα levels during endotoxemia in mice. In vitro pharmacological inhibition of NAMPT reduced the intracellular concentration of NAD and pro-inflammatory cytokine secretion by inflammatory cells. Thus, NAMPT links NAD metabolism to inflammatory cytokine secretion by leukocytes, and its inhibition might therefore have therapeutic efficacy in immune-mediated inflammatory disorders

Revascularization After Intravitreal Bevacizumab and Laser Therapy of Bilateral Retinal Vascular Occlusions in Incontinentia Pigmenti (Bloch-Sulzberger Syndrome)

No consensus exists for the treatment of retinopathy in incontinentia pigmenti (IP). Vascular ischemia leads to tractional retinal detachments if untreated. Ultra-widefield fluorescein angiography (FA) is used to follow the vascular status of the retina. A 13-week-old female with IP presented with bilateral retinal vascular occlusions in both eyes. Ultra-widefield FA showed reperfusion after treatment with intravitreal bevacizumab (IVB) and angiography-guided laser to the avascular retina. Anti-vascular endothelial growth factor treatment reduces neovascularization and allows for growth of retinal vessels. IVB and FA-guided laser to the avascular retina is an option in IP. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e33-e37.]