KATP Channel Opener Diazoxide Prevents Neurodegeneration: A New Mechanism of Action via Antioxidative Pathway Activation

Pharmacological modulation of ATP-sensitive potassium channels has become a promising new therapeutic approach for the treatment of neurodegenerative diseases due to their role in mitochondrial and cellular protection. For instance, diazoxide, a well-known ATP-sensitive potassium channel activator with high affinity for mitochondrial component of the channel has been proved to be effective in animal models for different diseases such as Alzheimer's disease, stroke or multiple sclerosis. Here, we analyzed the ability of diazoxide for protecting neurons front different neurotoxic insults in vitro and ex vivo. Results showed that diazoxide effectively protects NSC-34 motoneurons from glutamatergic, oxidative and inflammatory damage. Moreover, diazoxide decreased neuronal death in organotypic hippocampal slice cultures after exicitotoxicity and preserved myelin sheath in organotypic cerebellar cultures exposed to pro-inflammatory demyelinating damage. In addition, we demonstrated that one of the mechanisms of actions implied in the neuroprotective role of diazoxide is mediated by the activation of Nrf2 expression and nuclear translocation. Nrf2 expression was increased in NSC-34 neurons in vitro as well as in the spinal cord of experimental autoimmune encephalomyelitis animals orally administered with diazoxide. Thus, diazoxide is a neuroprotective agent against oxidative stress-induced damage and cellular dysfunction that can be beneficial for diseases such as multiple sclerosis

AAV-mediated expression of secreted and transmembrane αKlotho isoforms rescues relevant aging hallmarks in senescent SAMP8 mice

Senescence represents a stage in life associated with elevated incidence of morbidity and increased risk of mortality due to the accumulation of molecular alterations and tissue dysfunction, promoting a decrease in the organism's protective systems. Thus, aging presents molecular and biological hallmarks, which include chronic inflammation, epigenetic alterations, neuronal dysfunction, and worsening of physical status. In this context, we explored the AAV9-mediated expression of the two main isoforms of the aging-protective factor Klotho (KL) as a strategy to prevent these general age-related features using the senescence-accelerated mouse prone 8 (SAMP8) model. Both secreted and transmembrane KL isoforms improved cognitive performance, physical state parameters, and different molecular variables associated with aging. Epigenetic landscape was recovered for the analyzed global markers DNA methylation (5-mC), hydroxymethylation (5-hmC), and restoration occurred in the acetylation levels of H3 and H4. Gene expression of pro- and anti-inflammatory mediators in central nervous system such as TNF-α and IL-10, respectively, had improved levels, which were comparable to the senescence-accelerated-mouse resistant 1 (SAMR1) healthy control. Additionally, this improvement in neuroinflammation was supported by changes in the histological markers Iba1, GFAP, and SA β-gal. Furthermore, bone tissue structural variables, especially altered during senescence, recovered in SAMP8 mice to SAMR1 control values after treatment with both KL isoforms. This work presents evidence of the beneficial pleiotropic role of Klotho as an anti-aging therapy as well as new specific functions of the KL isoforms for the epigenetic regulation and aged bone structure alteration in an aging mouse model

The L-type voltage-gated calcium channel modulates microglial pro-inflammatory activity

Under pathological conditions, microglia, the resident CNS immune cells, become reactive and release pro-inflammatory cytokines and neurotoxic factors. We investigated whether this phenotypic switch includes changes in the expression of the L-type voltage-gated calcium channel (VGCC) in a rat model of N-methyl-d-aspartate-induced hippocampal neurodegeneration. Double immunohistochemistry and confocal microscopy evidenced that activated microglia express the L-type VGCC. We then analyzed whether BV2 microglia express functional L-type VGCC, and investigated the latter's role in microglial cytokine release and phagocytic capacity. Activated BV2 microglia express the CaV1.2 and CaV1.3 subunits of the L-type VGCC determined by reverse transcription-polymerase chain reaction, Western blot and immunocytochemistry. Depolarization with KCl induced a Ca2+ entry facilitated by Bay k8644 and partially blocked with nifedipine, which also reduced TNF-α and NO release by 40%. However, no nifedipine effect on BV2 microglia viability or phagocytic capacity was observed. Our results suggest that in CNS inflammatory processes, the L-type VGCC plays a specific role in the control of microglial secretory activity

Oral administration of the KATP channel opener diazoxide ameliorates disease progression in a murine model of multiple sclerosis

Background Multiple Sclerosis (MS) is an acquired inflammatory demyelinating disorder of the central nervous system (CNS) and is the leading cause of nontraumatic disability among young adults. Activated microglial cells are important effectors of demyelination and neurodegeneration, by secreting cytokines and others neurotoxic agents. Previous studies have demonstrated that microglia expresses ATP-sensitive potassium (KATP) channels and its pharmacological activation can provide neuroprotective and anti-inflammatory effects. In this study, we have examined the effect of oral administration of KATP channel opener diazoxide on induced experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Methods Anti-inflammatory effects of diazoxide were studied on lipopolysaccharide (LPS) and interferon gamma (IFNy)-activated microglial cells. EAE was induced in C57BL/6J mice by immunization with myelin oligodendrocyte glycoprotein peptide (MOG35-55). Mice were orally treated daily with diazoxide or vehicle for 15 days from the day of EAE symptom onset. Treatment starting at the same time as immunization was also assayed. Clinical signs of EAE were monitored and histological studies were performed to analyze tissue damage, demyelination, glial reactivity, axonal loss, neuronal preservation and lymphocyte infiltration. Results Diazoxide inhibited in vitro nitric oxide (NO), tumor necrosis factor alpha (TNF-¿) and interleukin-6 (IL-6) production and inducible nitric oxide synthase (iNOS) expression by activated microglia without affecting cyclooxygenase-2 (COX-2) expression and phagocytosis. Oral treatment of mice with diazoxide ameliorated EAE clinical signs but did not prevent disease. Histological analysis demonstrated that diazoxide elicited a significant reduction in myelin and axonal loss accompanied by a decrease in glial activation and neuronal damage. Diazoxide did not affect the number of infiltrating lymphocytes positive for CD3 and CD20 in the spinal cord. Conclusion Taken together, these results demonstrate novel actions of diazoxide as an anti-inflammatory agent, which might contribute to its beneficial effects on EAE through neuroprotection. Treatment with this widely used and well-tolerated drug may be a useful therapeutic intervention in ameliorating MS disease

Student nurses at Spanish universities and their attitude toward xenotransplantation

Introduction: Recent immunological and transgenic advances are a promising alternative using limited materials of human origin for transplantation. However, it is essential to achieve social acceptance of this therapy. Objective: To analyze the attitude of nursing students from Spanish universities toward organ xenotransplantation (XTx) and to determine the factors affecting their attitude. Materials and methods: Type of study: A sociological, multicentre, and observational study. Study population: Nursing students enrolled in Spain (n = 28,000). Sample size: A sample of 10 566 students estimating a proportion of 76% (99% confidence and precision of ±1%), stratified by geographical area and year of study. Instrument of measurement: A validated questionnaire (PCID‐XenoTx‐RIOS) was handed out to every student in a compulsory session. This survey was self‐administered and self‐completed voluntarily and anonymously by each student in a period of 5‐10 min. Statistical analysis: descriptive analysis, Student's t test, the chi‐square test, and a logistic regression analysis. Results: A completion rate: 84% (n = 8913) was obtained. If the results of XTx were as good as in human donation, 74% (n = 6564) would be in favor and 22% (n = 1946) would have doubts. The following variables affected this attitude: age (P < 0.001); sex (P < 0.001); geographical location (P < 0.001); academic year of study (P < 0.001); attitude toward organ donation (P < 0.001); belief in the possibility of needing a transplant (P < 0.001); discussion of transplantation with one's family (P < 0.001) and friends (P < 0.001); and the opinion of one's partner (P < 0.001). The following variables persisted in the multivariate analysis: being a male (OR = 1.436; P < 0.001); geographical location (OR = 1.937; P < 0.001); an attitude in favor of donation (OR = 1.519; P < 0.001); belief in the possibility of needing a transplant (OR = 1.497; P = 0.036); and having spoken about the issue with family (OR = 1.351; P < 0.001) or friends (OR = 1.240; P = 0.001). Conclusions: The attitude of nursing students toward organ XTx is favorable and is associated with factors of general knowledge about organ donation and transplantation and social interaction