scholarly journals Amphotericin B resistance in Leishmania mexicana: Alterations to sterol metabolism, lipid transport and oxidative stress response

2021 ◽  
Author(s):  
Edubiel A. Alpizar-Sosa ◽  
Nur Raihana Binti Ithnin ◽  
Wenbin Wei ◽  
Andrew W. Pountain ◽  
Stefan K. Weidt ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Amphotericin B ◽  
Defined Medium ◽  
Pentose Phosphate ◽  
Leishmania Mexicana ◽  
Methyl Transferase ◽  
Glucose Flux ◽  
Resistant Lines ◽  
And Oxidative Stress ◽  
Foetal Bovine Serum

AbstractAmphotericin B is increasingly used in treatment of leishmaniasis. Here, fourteen independent lines of Leishmania mexicana and one L. infantum line were selected for resistance to either amphotericin B or the related polyene antimicrobial, nystatin. Sterol profiling revealed that, in each line, the predominant ergostane-type sterol of wild-type cells was replaced by other sterol species. Broadly, two different profiles emerged among the resistant lines. Whole genome sequencing then showed that these distinct profiles were due either to mutations in the sterol methyl transferase (C24SMT) gene locus or the sterol C5 desaturase (C5DS) gene. In three lines an additional deletion of the miltefosine transporter was found. Differences in sensitivity to amphotericin B were apparent, depending on whether cells were grown in HOMEM, supplemented with foetal bovine serum, or a serum free defined medium (DM). These differences appeared to relate to the presence of lipids in the former. Metabolomic analysis after exposure to AmB showed that a large increase in glucose flux via the pentose phosphate pathway preceded cell death in cells sustained in HOMEM but not DM, indicating the oxidative stress was more significantly induced under HOMEM conditions. Several of the lines were tested for ability to infect macrophages and replicate as amastigote forms, alongside their ability to establish infections in mice. While several lines showed reduced virulence, at least one AmB resistant line displayed heightened virulence in mice whilst retaining its resistance phenotype, emphasising the risks of resistance emerging to this critical drug.

scholarly journals Neuroprotective Function of High Glycolytic Activity in Astrocytes: Common Roles in Stroke and Neurodegenerative Diseases

2021 ◽  
Vol 22 (12) ◽  
pp. 6568
Author(s):  
Shinichi Takahashi
Keyword(s):  
Oxidative Stress ◽  
Neurodegenerative Diseases ◽  
Aerobic Glycolysis ◽  
High Capacity ◽  
Pentose Phosphate ◽  
Reduced Form ◽  
Neuronal Excitation ◽  
Glucose Flux ◽  
Glycolytic Activity ◽  
Neuroprotective Function

Astrocytes (also, astroglia) consume huge amounts of glucose and produce lactate regardless of sufficient oxygen availability, indicating a high capacity for aerobic glycolysis. Glycolysis in astrocytes is activated in accordance with neuronal excitation and leads to increases in the release of lactate from astrocytes. Although the fate of this lactate remains somewhat controversial, it is believed to fuel neurons as an energy substrate. Besides providing lactate, astrocytic glycolysis plays an important role in neuroprotection. Among the minor pathways of glucose metabolism, glucose flux to the pentose-phosphate pathway (PPP), a major shunt pathway of glycolysis, is attracting research interest. In fact, PPP activity in astrocytes is five to seven times higher than that in neurons. The astrocytic PPP plays a key role in protecting neurons against oxidative stress by providing neurons with a reduced form of glutathione, which is necessary to eliminate reactive oxygen species. Therefore, enhancing astrocytic glycolysis might promote neuronal protection during acute ischemic stroke. Contrariwise, the dysfunction of astrocytic glycolysis and the PPP have been implicated in the pathogenesis of various neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis, since mitochondrial dysfunction and oxidative stress trigger and accelerate disease progression.

Association between calcitriol and paricalcitol with oxidative stress in patients with hemodialysis

2020 ◽  
pp. 1-8
Author(s):  
Hasan Haci Yeter ◽  
Berfu Korucu ◽  
Elif Burcu Bali ◽  
Ulver Derici
Keyword(s):  
Oxidative Stress ◽  
Vitamin D ◽  
Antioxidant Status ◽  
Total Antioxidant Status ◽  
Stress Index ◽  
Total Oxidant Status ◽  
Vitamin D Analog ◽  
Total Antioxidant ◽  
Oxidant Status ◽  
And Oxidative Stress

Abstract. Background: The pathophysiological basis of chronic kidney disease and its complications, including cardiovascular disease, are associated with chronic inflammation and oxidative stress. We investigated the effects of active vitamin D (calcitriol) and synthetic vitamin D analog (paricalcitol) on oxidative stress in hemodialysis patients. Methods: This cross-sectional study was composed of 83 patients with a minimum hemodialysis vintage of one year. Patients with a history of any infection, malignancy, and chronic inflammatory disease were excluded. Oxidative markers (total oxidant and antioxidant status) and inflammation markers (C-reactive protein and interleukin-6) were analyzed. Results: A total of 47% (39/83) patients were using active or analog vitamin D. Total antioxidant status was significantly higher in patients with using active or analog vitamin D than those who did not use (p = 0.006). Whereas, total oxidant status and oxidative stress index were significantly higher in patients with not using vitamin D when compared with the patients who were using vitamin D preparation (p = 0.005 and p = 0.004, respectively). On the other hand, total antioxidant status, total oxidant status, and oxidative stress index were similar between patients who used active vitamin D or vitamin D analog (p = 0.6; p = 0.4 and p = 0.7, respectively). Conclusion: The use of active or selective vitamin D analog in these patients decreases total oxidant status and increases total antioxidant status. Also, paricalcitol is as effective as calcitriol in decreasing total oxidant status and increasing total antioxidant status in patients with chronic kidney disease.

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