Protective effect of salicylates against hydrogen peroxide stress in yeast

Curcumin attenuates gentamicin and sodium salicylate ototoxic effects by modulating the nuclear factor-kappaB and apoptotic pathways in rats

This study aimed to investigate the effectiveness of curcumin (CCM) against gentamicin (GEN) and sodium salicylates (NaS)-induced ototoxic effects in rats. For 15 consecutive days, seven rat groups were given 1 mL/rat physiological saline orally, 1 mL/rat olive oil orally, 50 mg/kg bwt CCM orally, 120 mg/kg bwt GEN intraperitoneally, 300 mg/kg bwt NaS intraperitoneally, CCM+GEN, or CCM+NaS. The distortion product otoacoustic emission measurements were conducted. The rats' hearing function and balance have been behaviorally assessed using auditory startle response, Preyer reflex, and beam balance scale tests. The serum lipid peroxidation and oxidative stress biomarkers have been measured. Immunohistochemical investigations of the apoptotic marker caspase-3 and the inflammatory indicator nuclear factor kappa (NF-κB) in cochlear tissues were conducted. GEN and NaS exposure resulted in deficit hearing and impaired ability to retain balance. GEN and NaS exposure significantly decreased the reduced glutathione level and catalase activity but increased malondialdehyde content. GEN and NaS exposure evoked pathological alterations in cochlear and vestibular tissues and increased caspase-3 and NF-κB immunoexpression. CCM significantly counteracted the GEN and NaS injurious effects. These outcomes concluded that CCM could be a naturally efficient therapeutic agent against GEN and NaS-associated ototoxic side effects.

El Deib M. Protective Effect of Curcumin against Sodium Salicylate-Induced Oxidative Kidney Damage, Nuclear Factor-Kappa Dysregulation, and Apoptotic Consequences in Rats

This study examined the effect of sodium salicylates (SS), alone and in combination with curcumin (CUR), on kidney function and architecture in rats. Five rat groups were given 1 mL physiological saline/rat orally, 1 mL olive oil/rat orally, 50 mg CUR/kg bwt orally, 300 mg SS/kg bwt intraperitoneally, or CUR+SS for 15 days. The hematological indices, serum protein profile, serum electrolytes balance, oxidative stress, and lipid peroxidation of kidney tissues were assessed. The histopathological examination and immune expression of Caspase-3 and nuclear factor kappa (NF-κB) were conducted. The findings showed that SS injection induced nephrotoxic activity, including increased serum urea, creatinine, and uric acid levels. It also caused apparent pathological alterations with increased Caspase-3 and NF-κB immuno-expression. In addition, thrombocytopenia, leukocytosis, neutrophilia, hyponatremia, hypochloremia, hypocalcemia, and hypomagnesemia but not hyperkalemia and hyperphosphatemia were evident in SS-injected rats. Moreover, SS exposure increased serum α1 globulin, renal tissue malondialdehyde, and Caspase-3 levels but superoxide dismutase, glutathione peroxidase, and Bcl-2 levels declined. Meanwhile, CUR significantly counteracted the SS harmful impacts on kidneys but SS+CUR co-administration induced an anemic condition. Overall, CUR has an evident protective role against SS-induced renal damage, but the disturbed hematological alterations should be carefully taken into consideration in their combined use.

Curcumin mitigates neurotoxic and neurobehavioral changes of gentamicin and sodium salicylate in rats by adjusting oxidative stress and apoptosis

Currently, antibiotics and salicylates are the most highly consumed medications worldwide. The side effects of these pharmaceuticals on the nervous system have been little investigated. Thus, this study aimed to examine the influence of the gentamicin (GM) and sodium salicylates (SS) on neurobehavioral functions, including locomotors function, memory, and sensorimotor functions together with gamma-aminobutyric acid (GABA) neurotransmitter levels. Also, oxidative stress, lipid peroxidation, and apoptotic indicators of brain tissue were assessed. Additionally, the histopathological architecture of brain tissues was investigated. This study also evaluated the curcumin (CUR) efficacy to counteract the GM or SS induced neurotoxic impacts in rats. For this purpose, seven groups were administered physiological saline (1 ml/rat; orally), olive oil (1 ml/rat; orally), CUR (50 mg/kg bwt; orally), GM (120 mg/kg bwt; intraperitoneally), SS (300 mg /kg bwt; intraperitoneally), CUR + GM, or CUR + SS for consecutive 15 days. The results revealed that GM and SS exposure evoked impaired memory, sensorimotor deficit functions, and depressive-like behavior together with the depletion of GABA. GM and SS exposure elevated malondialdehyde and Caspase-3 levels, but total antioxidant capacity and Bcl-2 levels were reduced. Besides, GM and SS exposure induced distinct pathological perturbations in cerebral cortices and hippocampus tissues. CUR significantly reversed the GM and SS harmful impacts. In conclusion, these findings verified that CUR could be a biologically efficient protective intervention against GM and SS induced neurotoxic impacts and neurobehavioral aberrations.

Antagonism between salicylate and the cAMP signal controls yeast cell survival and growth recovery from quiescence

Aspirin and its main metabolite salicylate are promising molecules in preventing cancer and metabolic diseases. S. cerevisiae cells have been used to study some of their effects: (i) salicylate induces the reversible inhibition of both glucose transport and the biosyntheses of glucose-derived sugar phosphates, (ii) Aspirin/salicylate causes apoptosis associated with superoxide radical accumulation or early cell necrosis in MnSOD-deficient cells growing in ethanol or in glucose, respectively. So, treatment with (acetyl)-salicylic acid can alter the yeast metabolism and is associated with cell death. We describe here the dramatic effects of salicylate on cellular control of the exit from a quiescence state. The growth recovery of long-term stationary phase cells was strongly inhibited in the presence of salicylate, to a degree proportional to the drug concentration. At high salicylate concentration, growth reactivation was completely repressed and associated with a dramatic loss of cell viability. Strikingly, both of these phenotypes were fully suppressed by increasing the cAMP signal without any variation of the exponential growth rate. Upon nutrient exhaustion, salicylate induced a premature lethal cell cycle arrest in the budded-G2/M phase that cannot be suppressed by PKA activation. We discuss how the dramatic antagonism between cAMP and salicylate could be conserved and impinge common targets in yeast and humans. Targeting quiescence of cancer cells with stem-like properties and their growth recovery from dormancy are major challenges in cancer therapy. If mechanisms underlying cAMP-salicylate antagonism will be defined in our model, this might have significant therapeutic implications.

Omega-3 polyunsaturated fatty acids as an angelus custos to rescue patients from NSAID-induced gastroduodenal damage

Nonsteroidal anti-inflammat ory drugs (NSAIDs) are one of the drug types frequently prescribed for their analgesic, anti-inflammatory, and antithrombotic actions, but carry a risk of major gastroduodenal damage from mild erosive changes to serious ulceration leading to fatal outcomes. From the long history of willow tree bark and its extracts being applied for the relief of pain and fever, the synthesis of acetylsalicylic acid, the development of selective cyclooxygenase 2 inhibitors (coxibs), and the identification of a G-protein-coupled receptor for prostaglandin, the popular combination regimen of an NSAID and a proton pump inhibitor was invented, but development was continued for further improvement. With regard to major NSAID adverse effects, gastrointestinal (GI) and cardiovascular (CV) risks still remained as problems to be solved. In this review, it is shown that n-3 polyunsaturated fatty acid (PUFA) based NSAIDs can be an angelus custos, supported with facts that an intake of essential n-3 PUFAs orchestrates concerted protective actions against two notorious side effects of NSAIDs, the aforementioned GI risk and CV risk of NSAIDs. Since pills containing n-3 PUFAs, omega-3-acid ethyl ester capsules (Lovaza, Omarcor), have already been safely prescribed to prevent atherosclerosis through lessening lipid burdening, the introduction of a drug delivery system such as a gastroretentive form of n-3 PUFA based NSAIDs will highlight newer hope for GI safety under the guarantee of reduced CV risk. Because n-3 PUFAs have been proven to attenuate cytotoxicity, inhibit lipid-raft-associated harmful signaling, and relieve oxidative stress relevant to NSAIDs, n-3 PUFA based NSAIDs will be next-generation GI-safe NSAIDs.

Aspirin-induced apoptosis of yeast cells is associated with mitochondrial superoxide radical accumulation and NAD(P)H oxidation

In previous studies, we observed that aspirin, a promising cancer-preventive agent, induces apoptosis in mitochondrial manganese superoxide dismutase (MnSOD)-deficient Saccharomyces cerevisiae cells grown aerobically in ethanol medium. In this study, we show that aspirin-induced apoptosis is associated with a significant increase in mitochondrial and cytosolic O2 ·- and oxidation of mitochondrial NAD(P)H. A concomitant rise in the level of cytosolic CuZnSOD activity failed to compensate for mitochondrial MnSOD deficiency. However, an observed increase in activity of Escherichia coli FeSOD targeted to the mitochondrial matrix of the MnSOD-deficient yeast cells, markedly decreased aspirin-induced accumulation of mitochondrial O2 ·-, significantly increased the mitochondrial NAD(P)H level and rescued the apoptotic phenotype. Indeed, recombinant yeast cells expressing E. coli FeSOD behaved in a similar manner to the parent wild-type yeast cells with native mitochondrial MnSOD activity. Wild-type cells consistently showed a decrease in mitochondrial O2 ·- and an increase in mitochondrial NAD(P)H levels in the presence of aspirin in ethanol medium. In fact, in wild-type cells, our studies supported an antioxidant action of aspirin. Taken together, our results indicate that a pro-oxidant effect of aspirin occurring predominantly in cells with compromised mitochondrial redox balance may be enough to overcome antioxidant defences resulting in apoptosis, as observed in MnSOD-deficient yeast cells.

The proapoptotic effect of traditional and novel nonsteroidal anti-inflammatory drugs in mammalian and yeast cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used to treat pain, fever, and inflammation. However, mounting evidence shows that NSAIDs, such as aspirin, have very promising antineoplastic properties. The chemopreventive, antiproliferative behaviour of NSAIDs has been associated with both their inactivation of cyclooxygenases (COX) and their ability to induce apoptosis via pathways that are largely COX-independent. In this review, the various proapoptotic pathways induced by traditional and novel NSAIDs such as phospho-NSAIDs, hydrogen sulfide-releasing NSAIDs and nitric oxide-releasing NSAIDs in mammalian cell lines are discussed, as well as the proapoptotic effects of NSAIDs on budding yeast which retains the hallmarks of mammalian apoptosis. The significance of these mechanisms in terms of the role of NSAIDs in effective cancer prevention is considered.

Targeting oxidative stress response by green tea polyphenols: clinical implications

Green tea polyphenols, the most interesting constituent of green tea leaves, have been shown to have both pro-oxidant and antioxidant properties. Both pro-oxidant and antioxidant properties are expected to contribute to modulation of oxidative stress response under ideal optimal dosage regimens. Exposure to a low concentration of a pro-oxidant prior to exposure to oxidative stress induces the expression of genes that code for proteins that induce adaptation in a subsequent oxidative stress. On the other hand, exposure to an antioxidant concurrently with exposure to the oxidative stress affords protection through free radical scavenging or through other indirect antioxidant mechanisms. In any case, the optimal conditions that afford protection from oxidative stress should be defined for any substance with redox properties. Green tea polyphenols, being naturally occurring substances, seem to be an ideal option for the modulation of oxidative stress response. This paper reviews available data on the pro-oxidant and antioxidant properties of green tea polyphenols focusing on their potential on the modulation of oxidative stress response.

Does pharmacodynamic interaction of nonenzymatic antioxidants modify response to antioxidant therapy in the process of atherosclerosis?

A discrepancy exists between clinical trials and epidemiological studies on the effect of antioxidants on cardiovascular disease. This discrepancy could be attributed to the lack of knowledge on the effect of interaction of exogenous antioxidant supplementation with one another or on the effect of interaction of exogenously administered antioxidant vitamins with endogenous ones. This study attempts a systematic review of available data on possible synergistic, additive, or antagonistic action of nonenzymatic antioxidants in atherosclerosis. Electronic databases were searched with the available search terms up to and including February 2010. Eligibility criteria were full publications, clinical trials, epidemiological studies, or in vitro or in vivo studies that investigated the effect of pharmacodynamic interaction of 2 or more antioxidants in the process of atherosclerosis and /or the mechanism of interaction. Eligible clinical trials should have at least 4 arms, 1 arm for the study of each antioxidant alone, 1 for the effect of both antioxidants, and 1 arm for the effect of placebo. In vitro data as well as the limited number of identified randomized clinical trials suggested that coadministration of antioxidants results in synergistic or additive interaction in the process of atherosclerosis. No study demonstrated antagonistic interaction between antioxidants.

Too much of a good thing: long-term treatment with salicylate strengthens outer hair cell function but impairs auditory neural activity

Aspirin has been extensively used in clinical settings. Its side effects on auditory function, including hearing loss and tinnitus, are considered as temporary. A recent promising finding is that chronic treatment with high-dose salicylate (the active ingredient of aspirin) for several weeks enhances expression of the outer hair cell (OHC) motor protein (prestin), resulting in strengthened OHC electromotility and enhanced distortion product otoacoustic emissions (DPOAE). To follow up on these observations, we carried out two studies, one planned study of age-related hearing loss restoration and a second unrelated study of salicylate-induced tinnitus. Rats of different strains and ages were injected with salicylate at a dose of 200 mg/kg/day for 5 days per week for 3 weeks or at higher dose levels (250-350 mg/kg/day) for 4 days per week for 2 weeks. Unexpectedly, while an enhanced or sustained DPOAE was seen, permanent reductions in the amplitude of the cochlear compound action potential (CAP) and the auditory brainstem response (ABR) were often observed after the chronic salicylate treatment. The mechanisms underlying these unexpected, permanent salicylate-induced reductions in neural activity are discussed.