Novel optical assessments of tissue composition and viability using fluorescence spectroscopy and tissue oxygenation spectrophotometry in patients with systemic sclerosis: a pilot study

Abstract

The results of this pilot study demonstrate the potential diagnostic utility of FS and TOS assessments in SSc patients and further work is now needed to validate these techniques prospectively in a larger group of SSc patients across the spectrum of the disease, and also patients with other types of vasculopathy and conditions that can cause skin fibrosis.

State-of-the-art technologies provide new insights linking skin and blood vessel abnormalities in SSc-related disorders

“…Increased oxidative stress, observed as an increase in skin autofluorescence, has been observed in patients with SSc in previous studies ( Allen et al, 2018 ; Murray et al, 2012 ; Dadoniene et al, 2015 ). In previous work we found increased oxidative stress (versus controls) at the proximal finger, hand and forearm but not at the distal finger ( Murray et al, 2012 ).…”

“…In previous work we found increased oxidative stress (versus controls) at the proximal finger, hand and forearm but not at the distal finger ( Murray et al, 2012 ). Allen et al identified increased skin fluorescence and decreased oxygenation in 14 patients with SSc, compared to 9 controls ( Allen et al, 2018 ). Dadoniene et al measured oxidative stress at the forearm that was associated with changes in finger perfusion under occlusion in 47 patients with SSc versus 47 healthy controls ( Dadoniene et al, 2015 ).…”

“…Novel, non-invasive imaging methods are now available to assess cutaneous oxygenation (including near infra-red and multispectral imaging, ( Poxon et al, 2014 ; Jalil et al, 2018 ; Gargani et al, 2019 ; Allen et al, 2018 )) and oxidative stress ( Allen et al, 2018 ; Lutgers et al, 2006 ; Mulder et al, 2006 ; De Leeuw et al, 2006 ; Meerwaldt et al, 2007 ). These allow, for the first time, non-invasive investigation of inter-relationships between these two mechanistic pathways and different SSc-associated cutaneous abnormalities: microvascular structural changes (assessed using nailfold capillaroscopy), reduced perfusion (assessed using laser Doppler imaging) and skin thickening (assessed using high-frequency ultrasound).…”

Oxidative Stress Induced by Reactive Oxygen Species (ROS) and NADPH Oxidase 4 (NOX4) in the Pathogenesis of the Fibrotic Process in Systemic Sclerosis: A Promising Therapeutic Target

“…Regarding the fibrotic process, the functional relevance of the elevated oxidative stress components in the circulation of SSc patients was evidenced in one study showing that sera from patients with SSc pulmonary hypertension caused oxidative stress-induced stimulation of collagen synthesis in human pulmonary smooth muscle cells in vitro [ 51 ], and the demonstration by Sambo et al [ 8 ], in which the increased levels of ROS in SSc dermal fibroblasts resulted in the establishment of a pro-fibrotic phenotype in these cells. More recently, extensive investigations have assessed cutaneous oxidative stress in SSc, employing novel quantitative methods including fluorescence spectroscopy and tissue oxygenation spectrophotometry of affected SSc skin [ 52 , 53 ]. These studies suggested that the structural and functional microvascular abnormalities characteristic of the SSc vasculopathy cause tissue hypoxia and that as a result, there is increased oxidative stress in the affected tissues [ 52 , 53 ].…”

“…More recently, extensive investigations have assessed cutaneous oxidative stress in SSc, employing novel quantitative methods including fluorescence spectroscopy and tissue oxygenation spectrophotometry of affected SSc skin [ 52 , 53 ]. These studies suggested that the structural and functional microvascular abnormalities characteristic of the SSc vasculopathy cause tissue hypoxia and that as a result, there is increased oxidative stress in the affected tissues [ 52 , 53 ]. Furthermore, several studies have indicated that the increased oxidative stress induced by ROS alterations is reflected in the extent and severity of cutaneous fibrotic and skin thickening in these patients [ 24 , 27 , 54 , 55 ].…”