Frontiers in research series: The pathophysiological significance of sulphur-containing gases. Introduction

Rational Construction of a Mitochondria-Targeted Reversible Fluorescent Probe with Intramolecular FRET for Ratiometric Monitoring Sulfur Dioxide and Formaldehyde

Sulfur dioxide (SO₂) and formaldehyde (FA) are important species that maintain redox homeostasis in life and are closely related to many physiological and pathological processes. Therefore, it is of great significance to realize the reversible monitoring of them at the intracellular level. Here, we synthesized a reversible ratiometric fluorescent probe through a reasonable design, which can sensitively monitor SO₂ derivatives and FA, and the detection limit can reach 0.16 μM. The probe can specifically target mitochondria and successfully monitor the fluctuations of SO₂ and FA in living cells. It also works well in the detection of SO₂ and FA in zebrafish. This high-performance probe is expected to find broad in vitro and in vivo applications.

Increased Endogenous Sulfur Dioxide Involved in the Pathogenesis of Postural Tachycardia Syndrome in Children: A Case-Control Study

Background

The pathogenesis of postural tachycardia syndrome (POTS) remains unclear. This study aimed to explore the changes and significance of sulfur dioxide (SO₂) in patients with POTS.

Methods

The study included 31 children with POTS and 27 healthy children from Peking University First Hospital between December 2013 and October 2015. A detailed medical history, physical examination results, and demographic characteristics were collected. Hemodynamics was recorded and the plasma SO₂was determined.

Results

The plasma SO₂was significantly higher in POTS children compared to healthy children (64.0 ± 20.8 μmol/L vs. 27.2 ± 9.6 μmol/L, respectively, P < 0.05). The symptom scores in POTS were positively correlated with plasma SO₂levels (r = 0.398, P < 0.05). In all the study participants, the maximum heart rate (HR) was positively correlated with plasma levels of SO₂(r = 0.679, P < 0.01). The change in systolic blood pressure from the supine to upright (ΔSBP) in POTS group was smaller than that in the control group (P < 0.05). The ΔSBP was negatively correlated with baseline plasma SO₂levels in all participants (r = -0.28, P < 0.05). In the control group, ΔSBP was positively correlated with the plasma levels of SO₂(r = 0.487, P < 0.01). The change in HR from the supine to upright in POTS was obvious compared to that of the control group. The area under curve was 0.967 (95% confidence interval: 0.928-1.000), and the cutoff value of plasma SO₂ level >38.17 μmol/L yielded a sensitivity of 90.3% and a specificity of 92.6% for predicting the diagnosis of POTS.

Conclusions

Increased endogenous SO₂levels might be involved in the pathogenesis of POTS.

Sulfur-containing gaseous signal molecules, ion channels and cardiovascular diseases

Sulfur-containing gaseous signal molecules including hydrogen sulphide and sulfur dioxide were previously recognized as toxic gases. However, extensive studies have revealed that they can be generated in the cardiovascular system via a sulfur-containing amino acid metabolic pathway, and have an important role in cardiovascular physiology and pathophysiology. Ion channels are pore-forming membrane proteins present in the membrane of all biological cells; their functions include the establishment of a resting membrane potential and the control of action potentials and other electrical signals by conducting ions across the cell membrane. Evidence has now accumulated suggesting that the sulfur-containing gaseous signal molecules are important regulators of ion channels and transporters. The aims of this review are (1) to discuss the recent experimental evidences in the cardiovascular system regarding the regulatory effects of sulfur-containing gaseous signal molecules on a variety of ion channels, including ATP-sensitive potassium, calcium-activated potassium, voltage-gated potassium, L- and T-type calcium, transient receptor potential and chloride and sodium channels, and (2) to understand how the gaseous signal molecules affect ion channels and cardiovascular diseases.

LINKED ARTICLES

This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.

Sulfur dioxide preconditioning increases antioxidative capacity in rat with myocardial ischemia reperfusion (I/R) injury

BACKGROUND

The study was designed to explore if sulfur dioxide (SO2) preconditioning increased antioxidative capacity in rat with myocardial ischemia reperfusion (I/R) injury.

METHODS

The myocardial I/R model was made by left coronary artery ligation for 30min and reperfusion for 120min in rats. Myocardial infarct size and plasma lactate dehydrogenase (LDH) and creatine kinase (CK) activities, plasma superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and glutathione (GSH) changes were detected for the rats. The contents of myocardial hydrogen sulfide (H2S) and nitric oxide (NO) were measured. Myocardial protein expressions of SOD1, SOD2, cystathionine γ-lyase (CSE) and iNOS were tested using Western blot.

RESULTS

Myocardial infarction developed and plasma CK and LDH activities were significantly increased in I/R group compared with those in control group, but SO2 preconditioning significantly reduced myocardial infarct size, and plasma CK and LDH activities. SO2 preconditioning successfully increased plasma SOD, GSH and GSH-Px levels and myocardial SOD1 protein expression, but decreased MDA level in rats of I/R group. Compared with controls, the myocardial H2S level and CSE expression were decreased after I/R, but myocardial NO level and iNOS expression were increased. With the treatment of SO2, myocardial H2S level and CSE expression were increased, but myocardial NO level and iNOS expression were decreased compared with those in I/R group.

CONCLUSIONS

SO2 preconditioning could significantly reduce I/R-induced myocardial injury in vivo in association with increased myocardial antioxidative capacity, upregulated myocardial H2S/CSE pathway but downregulated NO/iNOS pathway.