Early Effects of Hyperbaric Oxygen on Inducible Nitric Oxide Synthase Activity/Expression in Lymphocytes of Type 1 Diabetes Patients: A Prospective Pilot Study

Ivana Resanovic,Davorka Milacic,Aleksandra Jovanovic,Radmilo Isakovic,Emina Sudar-Milovanovic,Esma R Isenovic,Bozidarka Zaric,Zoran Gluvic

doi:10.1155/2019/2328505

Ivana Resanovic, Davorka Milacic + Show 6 more

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https://doi.org/10.1155/2019/2328505

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Abstract

This study aimed at examining the early effects of hyperbaric oxygen therapy (HBOT) on inducible nitric oxide synthase (iNOS) activity/expression in lymphocytes of type 1 diabetes mellitus (T1DM) patients. A group of 19 patients (mean age: 63 ± 2.1) with T1DM and with the peripheral arterial disease were included in this study. Patients were exposed to 10 sessions of HBOT in the duration of 1 h to 100% oxygen inhalation at 2.4 ATA. Blood samples were collected for the plasma C-reactive protein (CRP), plasma free fatty acid (FFA), serum nitrite/nitrate, and serum arginase activity measurements. Expression of iNOS and phosphorylation of p65 subunit of nuclear factor-κB (NFκB-p65), extracellular-regulated kinases 1/2 (ERK1/2), and protein kinase B (Akt) were examined in lymphocyte lysates by Western blot. After exposure to HBOT, plasma CRP and FFA were significantly decreased (p < 0.001). Protein expression of iNOS and serum nitrite/nitrate levels were decreased (p < 0.01), while serum arginase activity was increased (p < 0.05) versus before exposure to HBOT. Increased phosphorylation of NFκB-p65 at Ser536 (p < 0.05) and decreased level of NFκB-p65 protein (p < 0.001) in lymphocytes of T1DM patients were observed after HBOT. Decreased phosphorylation of ERK1/2 (p < 0.05) and Akt (p < 0.05) was detected after HBOT. Our results indicate that exposure to HBO decreased iNOS activity/expression via decreasing phosphorylation of ERK1/2 and Akt followed by decreased activity of NFκB.

Highlights

Diabetes mellitus (DM) type 1 (T1DM) is a multifactorial autoimmune disease associated with significant morbidity and mortality related to microvascular and macrovascular complications [1, 2]
The serum nitrite/nitrate concentration (Figure 2(a)) was decreased by 29%, while serum arginase activity was increased by 32% after exposure to hyperbaric oxygen therapy (HBOT) (Figure 2(b))
Since the promoter of inducible nitric oxide (NO) synthase (iNOS) gene is the binding site for nuclear factor-κB (NFκB) transcription factor [21], we further examined whether NFκB is involved in HBOT downregulation of iNOS activity/expression by measuring p65 subunit level of NFκB (Figure 3)

Summary

Introduction

Diabetes mellitus (DM) type 1 (T1DM) is a multifactorial autoimmune disease associated with significant morbidity and mortality related to microvascular and macrovascular complications [1, 2]. T1DM is associated with abnormal synthesis of nitric oxide (NO) via activation of inducible NO synthase (iNOS) [3, 4], and an increased level of iNOS enzyme is associated with DM-related vascular complications [5,6,7,8]. The iNOS gene expression is stimulated through activation of transcription factors, such as nuclear factor-κB (NFκB). An increase in oxygen arterial partial pressure in hyperbaric conditions promotes better solubility of plasma oxygen. This further results in the preservation of vitality of tissues, reversibly damaged by atherosclerosis-induced ischemia, simultaneously with microcirculation restoration [12].

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