Inhibitory effects of alpha-lipoic acid on oxidative stress in the rostral ventrolateral medulla in rats with salt-induced hypertension

The Multifaceted Role of Alpha-Lipoic Acid in Cancer Prevention, Occurrence, and Treatment

Alpha-lipoic acid (ALA) is a naturally occurring compound synthesized by mitochondria and widely distributed in both animal and plant tissues. It primarily influences cellular metabolism and oxidative stress networks through its antioxidant properties and is an important drug for treating metabolic diseases associated with oxidative damage. Nevertheless, research indicates that the mechanism by which ALA affects cancer cells is distinct from that observed in normal cells, exhibiting pro-oxidative properties. Therefore, this review aims to describe the main chemical and biological functions of ALA in the cancer environment, including its mechanisms and effects in tumor prevention and anticancer activity, as well as its role as an adjunctive drug in cancer therapy. We specifically focus on the interactions between ALA and various carcinogenic and anti-carcinogenic pathways and discuss ALA's pro-oxidative capabilities in the unique redox environment of cancer cells. Additionally, we elaborate on ALA's roles in nanomedicine, hypoxia-inducible factors, and cancer stem cell research, proposing hypotheses and potential explanations for currently unresolved issues.

Therapeutic Effect of Alpha Lipoic Acid in a Rat Preclinical Model of Preeclampsia: Focus on Maternal Signs, Fetal Growth and Placental Function

Chronic hypertension is a major risk factor for preeclampsia (PE), associated with significant maternal and neonatal morbidity. We previously demonstrated that pregnant stroke-prone spontaneously hypertensive rats (SHRSP) display a spontaneous PE-like phenotype with distinct placental, fetal, and maternal features. Here, we hypothesized that supplementation with alpha lipoic acid (ALA), a potent antioxidant, during early pregnancy could ameliorate the PE phenotype in this model. To test this hypothesis, timed pregnancies were established using 10 to 12-week-old SHRSP females (n = 19-16/group), which were assigned to two treatment groups: ALA (injected intraperitoneally with 25 mg/kg body weight ALA on gestation day (GD1, GD8, and GD12) or control, receiving saline following the same protocol. Our analysis of maternal signs showed that ALA prevented the pregnancy-dependent maternal blood pressure rise (GD14 blood pressure control 169.3 ± 19.4 mmHg vs. 146.1 ± 13.4 mmHg, p = 0.0001) and ameliorated renal function, as noted by the increased creatinine clearance and improved glomerular histology in treated dams. Treatment also improved the fetal growth restriction (FGR) phenotype, leading to increased fetal weights (ALA 2.19 ± 0.5 g vs. control 1.98 ± 0.3 g, p = 0.0074) and decreased cephalization indexes, indicating a more symmetric fetal growth pattern. This was associated with improved placental efficiency, decreased oxidative stress marker expression on GD14, and serum soluble fms-like tyrosine kinase 1 (sFlt1) levels on GD20. In conclusion, ALA supplementation mitigated maternal signs and improved placental function and fetal growth in SHRSP pregnancies, emerging as a promising therapy in pregnancies at high risk for PE.

Effects of Antioxidant Combinations on the Renal Toxicity Induced Rats by Gold Nanoparticles

This study investigated some possible mechanisms underlying the nephrotoxic effect of gold nanoparticles (AuNPs) in rats and compared the protective effects of selected known antioxidants-namely, melanin, quercetin (QUR), and α-lipoic acid (α-LA). Rats were divided into five treatment groups (eight rats per group): control, AuNPs (50 nm), AuNPs + melanin (100 mg/kg), AuNPs + QUR (200 mg/kg), and AuNPs + α-LA (200 mg/kg). All treatments were administered i.p., daily, for 30 days. AuNPs promoted renal glomerular and tubular damage and impaired kidney function, as indicated by the higher serum levels of creatinine (Cr), urinary flow, and urea and albumin/Cr ratio. They also induced oxidative stress by promoting mitochondrial permeability transition pore (mtPTP) opening, the expression of NOX4, increasing levels of malondialdehyde (MDA), and suppressing glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). In addition, AuNPs induced renal inflammation and apoptosis, as evidenced by the increase in the total mRNA and the cytoplasmic and nuclear levels of NF-κB, mRNA levels of Bax and caspase-3, and levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Treatment with melanin, QUR, and α-lipoic acid (α-LA) prevented the majority of these renal damage effects of AuNPs and improved kidney structure and function, with QUR being the most powerful. In conclusion, in rats, AuNPs impair kidney function by provoking oxidative stress, inflammation, and apoptosis by suppressing antioxidants, promoting mitochondrial uncoupling, activating NF-κB, and upregulating NOX4. However, QUR remains the most powerful drug to alleviate this toxicity by reversing all of these mechanisms.

Oxidative Stress, Antioxidants and Hypertension

As a major cause of morbidity and mortality globally, hypertension remains a serious threat to global public health. Despite the availability of many antihypertensive medications, several hypertensive individuals are resistant to standard treatments, and are unable to control their blood pressure. Regulation of the renin-angiotensin-aldosterone system (RAAS) controlling blood pressure, activation of the immune system triggering inflammation and production of reactive oxygen species, leading to oxidative stress and redox-sensitive signaling, have been implicated in the pathogenesis of hypertension. Thus, besides standard antihypertensive medications, which lower arterial pressure, antioxidant medications were tested to improve antihypertensive treatment. We review and discuss the role of oxidative stress in the pathophysiology of hypertension and the potential use of antioxidants in the management of hypertension and its associated organ damage.

NADPH oxidase family proteins: signaling dynamics to disease management

Reactive oxygen species (ROS) are pervasive signaling molecules in biological systems. In humans, a lack of ROS causes chronic and extreme bacterial infections, while uncontrolled release of these factors causes pathologies due to excessive inflammation. Professional phagocytes such as neutrophils (PMNs), eosinophils, monocytes, and macrophages use superoxide-generating NADPH oxidase (NOX) as part of their arsenal of antimicrobial mechanisms to produce high levels of ROS. NOX is a multisubunit enzyme complex composed of five essential subunits, two of which are localized in the membrane, while three are localized in the cytosol. In resting phagocytes, the oxidase complex is unassembled and inactive; however, it becomes activated after cytosolic components translocate to the membrane and are assembled into a functional oxidase. The NOX isoforms play a variety of roles in cellular differentiation, development, proliferation, apoptosis, cytoskeletal control, migration, and contraction. Recent studies have identified NOX as a major contributor to disease pathologies, resulting in a shift in focus on inhibiting the formation of potentially harmful free radicals. Therefore, a better understanding of the molecular mechanisms and the transduction pathways involved in NOX-mediated signaling is essential for the development of new therapeutic agents that minimize the hyperproduction of ROS. The current review provides a thorough overview of the various NOX enzymes and their roles in disease pathophysiology, highlights pharmacological strategies, and discusses the importance of computational modeling for future NOX-related studies.

Supplementation with a putative calorie restriction mimetic micronutrient blend increases glutathione concentrations and improves neuroenergetics in brain of healthy middle-aged men and women

BACKGROUND

Caloric restriction (CR) without micronutrient deficiency has been shown to increase both lifespan and healthspan. In animals, CR has been demonstrated to increase glutathione (GSH), a neuroprotective antioxidant, in the brain and preserve brain mitochondrial function by altering neuroenergetics. In humans it has been associated with improvements in mood states and cognitive function. However, most CR studies have employed a 30-60% reduction in calories which is likely too stringent for most people to adhere to long-term. Thus, there is an unmet need for nutritional supplements which can mimic the biological effects of CR, without the need for calorie limitations.

AIM

The purpose of the present randomized, placebo-controlled clinical trial was to use Proton (¹H) Magnetic Resonance Spectroscopic (MRS) measurements to determine non-invasively whether a blend of micronutrients, a putative CR mimetic, positively modulates metabolites related to neuroprotection and neuroenergetics in the brain.

METHODS

Healthy middle-aged men and women (N = 63 [33 women]; age: 40-60 years) were randomized in a double-blind manner to 6 weeks supplementation with either the putative CR mimetic or placebo. At baseline and 6 weeks, subjects underwent MRS at 3 T to investigate changes in brain chemistry, including the neurometabolites: GSH, Glutamate (Glu), Glutamine (Gln) and N-Acetylaspartate (NAA).

RESULTS

GSH, a marker of antioxidant and cellular redox status, increased in the brain of participants in the supplement group. The supplement group also showed an increase in the Glu/Gln ratio, a marker of excitatory neurotransmission and bioenergetics. A trend for an increase in NAA/H₂O, a marker of neuronal integrity, was observed in females in the supplement group.

CONCLUSIONS

The present study reveals that 6-weeks daily supplementation with a micronutrient blend elicits positive changes in brain neurochemistry. This is the first study to demonstrate that a putative CR mimetic increases brain GSH concentrations and improves neuroprotection and neuroenergetics in the brain of healthy humans. This study was registered at www.clinicaltrials.gov as NCT02439983.

Gut microbiota and neuroinflammation in pathogenesis of hypertension: A potential role for hydrogen sulfide

Inflammation and gut dysbiosis are hallmarks of hypertension (HTN). Hydrogen sulfide (H2S) is an important freely diffusing molecule that modulates the function of neural, cardiovascular and immune systems, and circulating levels of H2S are reduced in animals and humans with HTN. While most research to date has focused on H₂S produced endogenously by the host, H2S is also produced by the gut bacteria and may affect the host homeostasis. Here, we review an association between neuroinflammation and gut dysbiosis in HTN, with special emphasis on a potential role of H2S in this interplay.

Differential impacts of brain stem oxidative stress and nitrosative stress on sympathetic vasomotor tone

Based on work-done in the rostral ventrolateral medulla (RVLM), this review presents four lessons learnt from studying the differential impacts of oxidative stress and nitrosative stress on sympathetic vasomotor tone and their clinical and therapeutic implications. The first lesson is that an increase in sympathetic vasomotor tone because of augmented oxidative stress in the RVLM is responsible for the generation of neurogenic hypertension. On the other hand, a shift from oxidative stress to nitrosative stress in the RVLM underpins the succession of increase to decrease in sympathetic vasomotor tone during the progression towards brain stem death. The second lesson is that, by having different cellular sources, regulatory mechanisms on synthesis and degradation, kinetics of chemical reactions, and downstream signaling pathways, reactive oxygen species and reactive nitrogen species should not be regarded as a singular moiety. The third lesson is that well-defined differential roles of oxidative stress and nitrosative stress with distinct regulatory mechanisms in the RVLM during neurogenic hypertension and brain stem death clearly denote that they are not interchangeable phenomena with unified cellular actions. Special attention must be paid to their beneficial or detrimental roles under a specific disease or a particular time-window of that disease. The fourth lesson is that, to be successful, future antioxidant therapies against neurogenic hypertension must take into consideration the much more complicated picture than that presented in this review on the generation, maintenance, regulation or modulation of the sympathetic vasomotor tone. The identification that the progression towards brain stem death entails a shift from oxidative stress to nitrosative stress in the RVLM may open a new vista for therapeutic intervention to slow down this transition.

Neuroinflammation in hypertension: the renin-angiotensin system versus pro-resolution pathways

Overstimulation of the pro-inflammatory pathways within brain areas responsible for sympathetic outflow is well evidenced as a primary contributing factor to the establishment and maintenance of neurogenic hypertension. However, the precise mechanisms and stimuli responsible for promoting a pro-inflammatory state are not fully elucidated. Recent work has unveiled novel compounds derived from omega-3 polyunsaturated fatty acids (ω-3 PUFAs), termed specialized pro-resolving mediators (SPMs), which actively regulate the resolution of inflammation. Failure or dysregulation of the resolution process has been linked to a variety of chronic inflammatory and neurodegenerative diseases. Given the pathologic role of neuroinflammation in the hypertensive state, SPMs and their associated pathways may provide a link between hypertension and the long-standing association of dietary ω-3 PUFAs with cardioprotection. Herein, we review recent progress in understanding the RAS-driven pathophysiology of neurogenic hypertension, particularly in regards to the chronic low-grade neuroinflammatory response. In addition, we examine the potential for an impaired resolution of inflammation process in the context of hypertension.

Alpha-lipoic acid mitigates toxic-induced demyelination in the corpus callosum by lessening of oxidative stress and stimulation of polydendrocytes proliferation

Multiple Sclerosis (MS), is a disease that degenerates myelin in central nervous system (CNS). Reactive oxygen species (ROSs) are toxic metabolites, and accumulating data indicate that ROSs-mediated apoptosis of oligodendrocytes (OLGs) plays a major role in the pathogenesis of MS under oxidative stress conditions. In this study, we investigated the role of endogenous antioxidant alpha-lipoic acid (ALA) as ROSs scavenger in the OLGs loss and myelin degeneration during cuprizone (cup)-induced demyelination in the experimental model of MS. Our results have shown that ALA treatment significantly increased population of mature OLGs (MOG⁺ cells), as well as decreased oxidative stress (ROSs, COX-2 and PGE2) and apoptosis mediators (caspase-3 and Bax/Bcl2 ratio) in corpus callosum (CC). Surprisingly, ALA significantly stimulates population of NG2 chondroitin sulfate proteoglycan positive glia (NG2⁺ cells or polydendrocytes), from week 4 afterward. Accordingly ALA could prevents apoptosis, delays demyelination and recruits OLGs survival and regeneration mechanisms in CC. We conclude that ALA has protective effects against toxic demyelination via reduction of redox signaling, and alleviation of polydendrocytes vulnerability to excitotoxic challenge.

Preemptive Analgesic and Antioxidative Effect of Curcumin for Experimental Migraine

OBJECTIVE

Our study aimed to investigate the analgesic and antioxidative stress effects of Curcumin (CC) in experimental migraine induced by Nitroglycerin (NTG) on rats, compared with Indomethacin (ID) and Propranolol (PP) treatments.

MATERIAL AND METHODS

Five groups of 10 rats treated i.p. were investigated: control group (healthy rats) injected with saline solution (0.9%), NTG-control group injected with NTG (1 mg/100 gbw, bw = body weight), and three groups with pretreatment applied 30 min previous to the formalin test (NTG + CC group: Curcumin (10 mg/100 gbw), NTG + PP group: Propranolol (100 μg/100 gbw), and NTG + ID group: Indomethacin (0.5 mg/100 gbw)). Formalin test was performed and number of flinches and shakes were counted. Several oxidative stress parameters were also assessed.

RESULTS

The smallest values of malondialdehyde (MDA), nitric oxide (NOx), and total oxidative status (TOS) were observed on NTG + CC with significant differences as compared with the control group (p < 0.0001). The group pretreated with Curcumin proved significantly smaller number of flinches and shakes compared with both NTG + PP and NTG + ID.

CONCLUSION

Our study demonstrates a superior activity of Curcumin not only versus control, but also versus Propranolol and Indomethacin.