Bilobalide protects mitochondrial function in ovariectomized rats by up-regulation of mRNA and protein expression of cytochrome c oxidase subunit I

Ginkgolide With Intravenous Alteplase Thrombolysis in Acute Ischemic Stroke Improving Neurological Function: A Multicenter, Cluster-Randomized Trial (GIANT)

Background and Purpose: We aimed to investigate the effect of Ginkgolide® treatment on neurological function in patients receiving intravenous (IV) recombinant tissue plasminogen activator (rt-PA). Methods: This cluster randomized controlled trial included acute ischemic stroke patients in 24 centers randomized to intervention of intravenous Ginkgolide® or control group within the first 24 h after IV rt-PA therapy (IVT). Clinical outcome at 90 days was assessed with modified Rankin Scale (mRS) score and dichotomized into good outcome (0-2) and poor outcome (3-6). Hemorrhagic transformation represented the conversion of a bland infarction into an area of hemorrhage by computed tomography. Symptomatic intracerebral hemorrhage (sICH) was defined as cerebral hemorrhagic transformation in combination with clinical deterioration of National Institutes of Health Stroke Scale (NIHSS) score ≥4 points at 7-day or if the hemorrhage was likely to be the cause of the clinical deterioration. We performed logistic regression analysis and propensity score matching analysis to investigate the impact of Ginkgolide® treatment with IV rt-PA on good outcome, hemorrhagic transformation and sICH, respectively. Results: A total of 1113 patients were finally included and 513 (46.1%) were in the intervention group. Patients in the Ginkgolide® group were more likely to have good outcomes (78.6 vs. 66.7%, p < 0.01) and lower rate of sICH (0 vs. 2.72%, p < 0.01), compared with patients in the control group. The intra-cluster correlation coefficient (ICC) for good outcome at 90 days was 0.033. Binary logistic regression analysis revealed that treatment with Ginkgolide® was independently associated with 90-day mRS in patients with IV rt-PA therapy (OR 1.498; 95% CI 1.006-2.029, p = 0.009). After propensity score matching, conditional logistic regression showed intervention with Ginkgolide® was significantly associated with 90-day good outcome (OR 1.513; 95% CI 1.073-2.132, p = 0.018). No significant difference in hemorrhage transformation was seen between the 2 matched cohorts (OR 0.885; 95% CI 0.450-1.741, p = 0.724). Conclusion: Using Ginkgolide® within 24-hour after IV rt-PA is effective and safe and might be recommended in combination with rtPA therapy in acute ischemic stroke. Clinical Trial Registration: http://www.clinicaltrials.gov, identifier NCT03772847.

Bilobalide: A review of its pharmacology, pharmacokinetics, toxicity, and safety

Bilobalide is a natural sesquiterpene trilactone from Ginkgo biloba leaves. It has good water solubility and is widely used in food and pharmaceutical fields. In the last decade, a plethora of studies on the pharmacological activities of bilobalide has been conducted and demonstrated that bilobalide possessed an extensive range of pharmacological activities such as neuroprotective, antioxidative, antiinflammatory, anti-ischemic, and cardiovascular protective activities. Pharmacokinetic studies indicated that bilobalide may have the characteristics of rapid absorption, good bioavailability, wide distribution, and slow elimination. This review aims to summarize the advances in pharmacological, pharmacokinetics, toxicity, and safety studies of bilobalide in the last decade with an emphasis on its neuroprotective and antiinflammatory activities, to provide researchers with the latest information and point out the limitations of relevant research at the current stage and the aspects that should be strengthened in future research.

Dietary Nutrients and Prevention of Alzheimer's disease

Alzheimer's disease is an irrevocable, progressive brain disorder that gradually destroys memory and cognitive skills. One of the extensively studied method of preventing Alzheimer's disease (AD) disease progression is by providing nutritional diet. Several reports have shown that intake of nutritional elements as huperzine A, ursolic acid, vitamins etc. can directly influence pathogenesis of AD. Surprisingly, occurrence of metabolic disorders due to unhealthy diet has been known to be a major environmental causes for AD. It has been noted that AD disease severity can be controlled by supplementing dietary supplements containing huge amounts of health-promoting ingredients. These elements promote cell health, regeneration, and the anti-aging process that specifically interrupt the pathogenic pathways in AD development. Fortunately, incorporating changes in the nutritional content is inexpensive, easy, acceptable, safe, effective, and in most cases free from major adverse events. Many nutritional phytoconstituents such as flavonoids, alkaloids, and terpenoids are still being evaluated in the hope of identifying a successful therapy for AD. This review discusses the therapeutical potential of several key nutrients that have been researched for treating AD treatment and the method of their neuroprotective intervention.

The neuroprotective mechanisms of ginkgolides and bilobalide in cerebral ischemic injury: a literature review

The incidence and mortality of strokes have increased over the past three decades in China. Ischemic strokes can cause a sequence of detrimental events in patients, including increased permeability and dysfunction of the blood-brain barrier, brain edema, metabolic disturbance, endoplasmic reticulum stress, autophagy, oxidative stress, inflammation, neuron death and apoptosis, and cognitive impairment. Thrombolysis using recombinant tissue plasminogen activator (rtPA) and mechanical embolectomy with a retrievable stent are two recognized strategies to achieve reperfusion after a stroke. Nevertheless, rtPA has a narrow therapeutic timeframe, and mechanical embolectomy has limited rates of good neurological outcomes. EGb761 is a standardized and extensively studied extract of Ginkgo biloba leaves. The ginkgolides and bilobalide that constitute a critical part of EGb761 have demonstrated protective properties towards cerebral injury. Ginkgolides include Ginkgolide A (GA), Ginkgolide B (GB), Ginkgolide C (GC), Ginkgolide J (GJ), Ginkgolide K (GK), Ginkgolide L (GL), and Ginkgolide M (GM). This review seeks to elucidate the neuroprotective effects and mechanisms of ginkgolides, especially GA and GB, and bilobalide in cerebral injury following ischemic strokes.

Role of Estrogen and Other Sex Hormones in Brain Aging. Neuroprotection and DNA Repair

Aging is an inevitable biological process characterized by a progressive decline in physiological function and increased susceptibility to disease. The detrimental effects of aging are observed in all tissues, the brain being the most important one due to its main role in the homeostasis of the organism. As our knowledge about the underlying mechanisms of brain aging increases, potential approaches to preserve brain function rise significantly. Accumulating evidence suggests that loss of genomic maintenance may contribute to aging, especially in the central nervous system (CNS) owing to its low DNA repair capacity. Sex hormones, particularly estrogens, possess potent antioxidant properties and play important roles in maintaining normal reproductive and non-reproductive functions. They exert neuroprotective actions and their loss during aging and natural or surgical menopause is associated with mitochondrial dysfunction, neuroinflammation, synaptic decline, cognitive impairment and increased risk of age-related disorders. Moreover, loss of sex hormones has been suggested to promote an accelerated aging phenotype eventually leading to the development of brain hypometabolism, a feature often observed in menopausal women and prodromal Alzheimer's disease (AD). Although data on the relation between sex hormones and DNA repair mechanisms in the brain is still limited, various investigations have linked sex hormone levels with different DNA repair enzymes. Here, we review estrogen anti-aging and neuroprotective mechanisms, which are currently an area of intense study, together with the effect they may have on the DNA repair capacity in the brain.

Role of Estrogen and Other Sex Hormones in Brain Aging. Neuroprotection and DNA Repair

Aging is an inevitable biological process characterized by a progressive decline in physiological function and increased susceptibility to disease. The detrimental effects of aging are observed in all tissues, the brain being the most important one due to its main role in the homeostasis of the organism. As our knowledge about the underlying mechanisms of brain aging increases, potential approaches to preserve brain function rise significantly. Accumulating evidence suggests that loss of genomic maintenance may contribute to aging, especially in the central nervous system (CNS) owing to its low DNA repair capacity. Sex hormones, particularly estrogens, possess potent antioxidant properties and play important roles in maintaining normal reproductive and non-reproductive functions. They exert neuroprotective actions and their loss during aging and natural or surgical menopause is associated with mitochondrial dysfunction, neuroinflammation, synaptic decline, cognitive impairment and increased risk of age-related disorders. Moreover, loss of sex hormones has been suggested to promote an accelerated aging phenotype eventually leading to the development of brain hypometabolism, a feature often observed in menopausal women and prodromal Alzheimer's disease (AD). Although data on the relation between sex hormones and DNA repair mechanisms in the brain is still limited, various investigations have linked sex hormone levels with different DNA repair enzymes. Here, we review estrogen anti-aging and neuroprotective mechanisms, which are currently an area of intense study, together with the effect they may have on the DNA repair capacity in the brain.

Hormone deprivation alters mitochondrial function and lipid profile in the hippocampus

Mitochondrial dysfunction is a common hallmark in aging. In the female, reproductive senescence is characterized by loss of ovarian hormones, many of whose neuroprotective effects converge upon mitochondria. The functional integrity of mitochondria is dependent on membrane fatty acid and phospholipid composition, which are also affected during aging. The effect of long-term ovarian hormone deprivation upon mitochondrial function and its putative association with changes in mitochondrial membrane lipid profile in the hippocampus, an area primarily affected during aging and highly responsive to ovarian hormones, is unknown. To this aim, Wistar adult female rats were ovariectomized or sham-operated. Twelve weeks later, different parameters of mitochondrial function (O₂ uptake, ATP production, membrane potential and respiratory complex activities) as well as membrane phospholipid content and composition were evaluated in hippocampal mitochondria. Chronic ovariectomy reduced mitochondrial O₂ uptake and ATP production rates and induced membrane depolarization during active respiration without altering the activity of respiratory complexes. Mitochondrial membrane lipid profile showed no changes in cholesterol levels but higher levels of unsaturated fatty acids and a higher peroxidizability index in mitochondria from ovariectomized rats. Interestingly, ovariectomy also reduced cardiolipin content and altered cardiolipin fatty acid profile leading to a lower peroxidizability index. In conclusion, chronic ovarian hormone deprivation induces mitochondrial dysfunction and changes in the mitochondrial membrane lipid profile comparable to an aging phenotype. Our study provides insights into ovarian hormone loss-induced early lipidomic changes with bioenergetic deficits in the hippocampus that may contribute to the increased risk of Alzheimer's disease and other age-associated disorders observed in postmenopause.

Estrogen upregulates inflammatory signals through NF-κB, IFN-γ, and nitric oxide via Akt/mTOR pathway in the lymph node lymphocytes of middle-aged female rats

The alterations in the secretion of sex steroids, especially estrogen, in females throughout reproductive life and its decline with age alters the functions of the neuroendocrine-immune network and renders them susceptible to age-related diseases and cancers. This study investigates the mechanisms of estrogen-induced alterations in cell-mediated immune and inflammatory responses in the lymphocytes from lymph nodes (axillary and inguinal) of ovariectomized (OVX) middle-aged female rats. Ovariectomized middle-aged (MA) Sprague-Dawley female rats (n=8) were implanted with 17β-estradiol (E2) 30-day release pellets (0.6 and 300μg). At the end of the treatment period, lymph nodes (axillary and inguinal) were isolated and examined for serum 17β-estradiol, lymphoproliferation, cytokine production, expression of p-Akt, p-mTOR, p-IκB-α and p-NF-κB (p50 and p65), extent of lipid peroxidation, nitric oxide (NO) production, cytochrome c oxidase activity and reactive oxygen species (ROS) production. There was an OVX-related decline in serum 17β-estradiol level, Con A-induced lymphoproliferation, p-Akt and p-mTOR expression, and cytochrome c oxidase (COX) activity. E2 supplementation increased serum 17β-estradiol level, lymphoproliferation, expression of p-Akt, p-mTOR, p-IκB-α and p-NF-κB (p50 and p65), lipid peroxidation, IFN-γ, TNF-α, ROS and NO production, while it decreased IL-6 production. E2 mediates inflammatory responses by increasing the levels of NO and TNF-α by up regulating IFN-γ and simultaneously promotes aging through the generation of free radicals as reflected by increased lipid peroxidation and ROS production in lymph nodes. These findings may have wide implications to immunity and inflammatory disorders including autoimmune diseases predominantly prevalent in females.

Effect of physical exercise on changes in activities of creatine kinase, cytochrome c oxidase and ATP levels caused by ovariectomy

The reduction in the secretion of ovarian hormones, principally estrogen, is a consequence of menopause. Estrogens act primarily as female sex hormones, but also exert effects on different physiological systems including the central nervous system. The treatment normally used to reduce the symptoms of menopause is the hormone therapy, which seems to be effective in treating symptoms, but it may be responsible for adverse effects. Based on this, there is an increasing demand for alternative therapies that minimize signs and symptoms of menopause. In the present study we investigated the effect of ovariectomy and/or physical exercise on the activities of energy metabolism enzymes, such as creatine kinase (cytosolic and mitochondrial fractions), pyruvate kinase, succinate dehydrogenase, complex II, cytochrome c oxidase, as well as on ATP levels in the hippocampus of adult rats. Adult female Wistar rats with 90 days of age were subjected to ovariectomy (an animal model widely used to mimic the postmenopausal changes). Thirty days after the procedure, the rats were submitted to the exercise protocol, which was performed three times a week for 30 days. Twelve hours after the last training session, the rats were decapitated for subsequent biochemical analyzes. Results showed that ovariectomy did not affect the activities of pyruvate kinase, succinate dehydrogenase and complex II, but decreased the activities of creatine kinase (cytosolic and mitochondrial fractions) and cytochrome c oxidase. ATP levels were also reduced. Exercise did not produce the expected results since it was only able to partially reverse the activity of creatine kinase cytosolic fraction. The results of this study suggest that estrogen deficiency, which occurs as a result of ovariectomy, affects generation systems and energy homeostasis, reducing ATP levels in hippocampus of adult female rats.

Natural products as promising drug candidates for the treatment of Alzheimer's disease: molecular mechanism aspect

Alzheimer’s disease (AD) is the most common neurodegenerative disorder to date, with no curative or preventive therapy. Histopathological hallmarks of AD include deposition of β-amyloid plaques and formation of neurofibrillary tangles. Extent studies on pathology of the disease have made important discoveries regarding mechanism of disease and potential therapeutic targets. Many cellular changes including oxidative stress, disruption of Ca2+ homeostasis, inflammation, metabolic disturbances, and accumulation of unfolded/misfolded proteins can lead to programmed cell death in AD. Despite intensive research, only five approved drugs are available for the management of AD. Hence, there is a need to look at alternative therapies. Use of natural products and culinary herbs in medicine has gained popularity in recent years. Several natural substances with neuroprotective effects have been widely studied. Most of these compounds have remarkable antioxidant properties and act mainly by scavenging free radical species. Some of them increase cell survival and improve cognition by directly affecting amyloidogenesis and programmed cell death pathways. Further studies on these natural products and their mechanism of action, parallel with the use of novel pharmaceutical drug design and delivery techniques, enable us to offer an addition to conventional medicine. This review discussed some natural products with potential neuroprotective properties against Aβ with respect to their mechanism of action.

Radix Achyranthis Bidentatae improves learning and memory capabilities in ovariectomized rats

Kidney-tonifying recipe can reduce the accumulation of advanced glycation end products, prevent neuronal degeneration and improve cognitive functions in ovariectomized rats. Radix Achyranthis Bidentatae alcohol extracts may dose-dependently inhibit non-enzymatic saccharification in vitro. This study aimed to examine the effect of Radix Achyranthis Bidentatae on advanced glycation end products and on learning and memory capabilities in ovariectomized rats. Ovariectomized rats were treated with Radix Achyranthis Bidentatae alcohol extracts (containing 1.5 g/kg crude drug) or 0.1% aminoguanidine for 12 weeks and behavioral testing was performed with the Y-electrical maze. This test revealed that Radix Achyranthis Bidentatae and aminoguanidine could improve the learning and memory capabilities of ovariectomized rats. Results of competitive enzyme-linked immunosorbent assay showed that treatment with Radix Achyranthis Bidentatae or aminoguanidine reduced the accumulation of advanced glycation end products in the frontal cortex of ovariectomized rats, while increasing content in the blood and urine. Biochemical tests showed that treatment with Radix Achyranthis Bidentatae or aminoguanidine decreased superoxide dismutase activity in the serum and frontal cortex, and increased serum levels of glutathione peroxidase in ovariectomized rats. In addition, there was no apparent effect on malondialdehyde levels. These experimental findings indicate that Radix Achyranthis Bidentatae inhibits production of advanced glycation end products and its accumulation in brain tissue, and improves learning and memory capabilities in ovariectomized rats. These effects may be associated with an anti-oxidative action of the extract.