Investigating the Ischaemic Phase of Skin NADH Fluorescence Dynamics in Recently Diagnosed Primary Hypertension: A Time Series Analysis

Regina Pawlak-Chomicka; Wojciech Chomicki; Tomasz Krauze; Paweł Uruski; Maria Guzik; Jarosław Piskorski; Andrzej Tykarski; Przemysław Guzik

doi:10.3390/jcm12041247

Investigating the Ischaemic Phase of Skin NADH Fluorescence Dynamics in Recently Diagnosed Primary Hypertension: A Time Series Analysis

J Clin Med. 2023 Feb 4;12(4):1247. doi: 10.3390/jcm12041247.

Authors

Regina Pawlak-Chomicka¹, Wojciech Chomicki², Tomasz Krauze³, Paweł Uruski¹, Maria Guzik⁴, Jarosław Piskorski⁵, Andrzej Tykarski¹, Przemysław Guzik³

Affiliations

¹ Department of Hypertensiology, Angiology and Internal Medicine, Poznan University of Medical Sciences, 61-848 Poznan, Poland.
² Department of Physics of Functional Materials, Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland.
³ Department of Cardiology-Intensive Therapy and Internal Medicine, Poznan University of Medical Sciences, 60-355 Poznan, Poland.
⁴ Faculty of Biology, Medicine and Health Sciences, University of Manchester, Manchester M13 9PL, UK.
⁵ Institute of Physics, University of Zielona Gora, 65-516 Zielona Gora, Poland.

Abstract

The reduced form of nicotinamide adenine dinucleotide (NADH) is crucial in cellular metabolism. During hypoxia, NADH accumulation results from anaerobic cytoplasmic glycolysis and impaired mitochondrial function. This study aimed to compare the dynamic changes in the 460-nm forearm skin fluorescence, which reflects cellular NADH content, during transient ischaemia between healthy individuals and patients with newly diagnosed, untreated essential hypertension (HA). Sixteen healthy volunteers and sixty-five patients with HA underwent non-invasive measurement of forearm skin NADH content using the Flow Mediated Skin Fluorescence (FMSF) method at rest and during a 100-s transient ischaemia induced by inflation of the brachial cuff. The fluorescent signal was sampled at 25 Hz. All samples were normalised to the end of the ischaemic phase, which is the most stable phase of the whole recording. Slope values of 1 s linear regressions were determined for every 25-sample neighbouring set. The 1-s slopes in the early phase of skin ischaemia, indicating quicker hypoxia-induced NADH accumulation in skin, were significantly higher in patients with HA than in healthy individuals. These findings suggest that some protecting mechanisms postponing the early consequences of early cellular hypoxia and premature NADH accumulation during skin ischaemia are impaired in patients with untreated HA. Further studies are needed to investigate this phenomenon.

Keywords: 460-nm skin fluoresce; arterial hypertension; flow-mediated skin fluorescence; ischaemia; mitochondria; nicotinamide adenine dinucleotide.

Grants and funding

This work was supported by an unrestricted research grant ANG/ZK/1/2017 (PI: PG) from the National Center for Research and Development in Poland as a part of the EU project funded by the European Regional Development Fund under the Smart Growth Operational Program, Grant No. POIR.01.01.01-00-0540/15.