Tag: endothelial nitric oxide synthase

Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study

Abstract:

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a multisystem chronic illness characterized by severe muscle fatigue, pain, dizziness, and brain fog. Many patients with ME/CFS experience orthostatic intolerance (OI), which is characterized by frequent dizziness, light-headedness, and feeling faint while maintaining an upright posture.
Despite intense investigation, the molecular mechanism of this debilitating condition is still unknown. OI is often manifested by cardiovascular alterations, such as reduced cerebral blood flow, reduced blood pressure, and diminished heart rate. The bioavailability of tetrahydrobiopterin (BH4), an essential cofactor of endothelial nitric oxide synthase (eNOS) enzyme, is tightly coupled with cardiovascular health and circulation.
To explore the role of BH4 in ME/CFS, serum samples of CFS patients (n = 32), CFS patients with OI only (n = 10; CFS + OI), and CFS patients with both OI and small fiber polyneuropathy (n = 12; CFS + OI + SFN) were subjected to BH4 ELISA. Interestingly, our results revealed that the BH4 expression is significantly high in CFS, CFS + OI, and CFS + OI + SFN patients compared to age-/gender-matched controls.
Finally, a ROS production assay in cultured microglial cells followed by Pearson correlation statistics indicated that the elevated BH4 in serum samples of CFS + OI patients might be associated with the oxidative stress response. These findings suggest that the regulation of BH4 metabolism could be a promising target for understanding the molecular mechanism of CFS and CFS with OI.
Source: Gottschalk CG, Whelan R, Peterson D, Roy A. Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study. International Journal of Molecular Sciences. 2023; 24(10):8713. https://doi.org/10.3390/ijms24108713 (Full text)

Role of polymorphisms of inducible nitric oxide synthase and endothelial nitric oxide synthase in idiopathic environmental intolerances

Abstract:

Oxidative stress and inflammation play a pathogenetic role in idiopathic environmental intolerances (IEI), namely, multiple chemical sensitivity (MCS), fibromyalgia (FM), and chronic fatigue syndrome (CFS). Given the reported association of nitric oxide synthase (NOS) gene polymorphisms with inflammatory disorders, we aimed to investigate the distribution of NOS2A -2.5 kb (CCTTT) n as well as Ser608Leu and NOS3 -786T>C variants and their correlation with nitrite/nitrate levels, in a study cohort including 170 MCS, 108 suspected MCS (SMCS), 89 FM/CFS, and 196 healthy subjects.

Patients and controls had similar distributions of NOS2A Ser608Leu and NOS3 -786T>C polymorphisms. Interestingly, the NOS3 -786TT genotype was associated with increased nitrite/nitrate levels only in IEI patients. We also found that the NOS2A -2.5 kb (CCTTT)11 allele represents a genetic determinant for FM/CFS, and the (CCTTT)16 allele discriminates MCS from SMCS patients. Instead, the (CCTTT)8 allele reduces by three-, six-, and tenfold, respectively, the risk for MCS, SMCS, and FM/CFS. Moreover, a short number of (CCTTT) repeats is associated with higher concentrations of nitrites/nitrates. Here, we first demonstrate that NOS3 -786T>C variant affects nitrite/nitrate levels in IEI patients and that screening for NOS2A -2.5 kb (CCTTT) n polymorphism may be useful for differential diagnosis of various IEI.

 

Source: De Luca C, Gugliandolo A, Calabrò C, Currò M, Ientile R, Raskovic D, Korkina L, Caccamo D. Role of polymorphisms of inducible nitric oxide synthase and endothelial nitric oxide synthase in idiopathic environmental intolerances. Mediators Inflamm. 2015;2015:245308. doi: 10.1155/2015/245308. Epub 2015 Mar 24. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4387900/ (Full article)