Effect of Ginkgo biloba extract on endotoxin-induced labyrinthitis

Unveiling the Role of Oxidative Stress in Cochlear Hair Cell Death: Prospective Phytochemical Therapeutics against Sensorineural Hearing Loss

Hearing loss represents a multifaceted and pervasive challenge that deeply impacts various aspects of an individual's life, spanning psychological, emotional, social, and economic realms. Understanding the molecular underpinnings that orchestrate hearing loss remains paramount in the quest for effective therapeutic strategies. This review aims to expound upon the physiological, biochemical, and molecular aspects of hearing loss, with a specific focus on its correlation with diabetes. Within this context, phytochemicals have surfaced as prospective contenders in the pursuit of potential adjuvant therapies. These compounds exhibit noteworthy antioxidant and anti-inflammatory properties, which hold the potential to counteract the detrimental effects induced by oxidative stress and inflammation-prominent contributors to hearing impairment. Furthermore, this review offers an up-to-date exploration of the diverse molecular pathways modulated by these compounds. However, the dynamic landscape of their efficacy warrants recognition as an ongoing investigative topic, inherently contingent upon specific experimental models. Ultimately, to ascertain the genuine potential of phytochemicals as agents in hearing loss treatment, a comprehensive grasp of the molecular mechanisms at play, coupled with rigorous clinical investigations, stands as an imperative quest.

Cardiovascular Activity of Ginkgo biloba-An Insight from Healthy Subjects

Ginkgo biloba is the oldest living tree species in the world. Despite less than encouraging clinical results, extracts from its leaves are among the most used herbal preparations in the prevention and treatment of cardiovascular diseases. Most data on the efficacy of Ginkgo biloba on cardiovascular disease is from clinical studies, with few results from healthy subjects. This paper aims to provide a comprehensive review of the mechanisms underlying the known beneficial cardiovascular activities of Ginkgo biloba. It displays myocardial suppressant and vasorelaxant activities ex vivo, potentiating endothelial-dependent and -independent pathways. It improves perfusion in different vascular beds, namely ocular, cochlear, cutaneous, cerebral, and coronary. Although scarce, evidence suggests that Ginkgo biloba displays a heterogeneous effect on tissue perfusion which is dependent on the individual elimination pathways. It displays an acceptable safety profile, with most reported adverse reactions constituting rare occurrences. Collectively, Ginkgo biloba positively impacts cardiovascular physiology, improving hemodynamics and organ perfusion. In the future, better controlled clinical studies should be performed in order to identify the target populations who may benefit the most from pharmacotherapeutic interventions involving Ginkgo biloba.

Potentialities of Ginkgo extract on toxicants, toxins, and radiation: a critical review

Exposure to toxins is a severe threat to human health and life in today's developing and industrialized world. Therefore, identifying a protective chemical could be valuable and fascinating in this case. The purpose of this article was to bring together thorough review of studies on Ginkgo biloba to aid in the creation of ways for delivering its phytoconstituents to treat toxicants and radiation. This review gathered and evaluated studies on the defensive impact of Ginkgo biloba extract (GBE) against toxicities caused by toxic chemical agents (such as lead, cadmium, and aluminum), natural toxins (for example, lipopolysaccharide-induced toxicity and damage, gossypol, latadenes, and lotaustralin), and radiation (for example, gamma, ultra-violet, and radio-frequency radiation). According to this review, GBE has a considerable therapeutic effect by influencing specific pathophysiological targets. Furthermore, GBE has antioxidant, anti-inflammatory, anti-apoptotic, and antigenotoxicity properties against various toxicities. These are due to flavone glycosides (primarily isorhamnetin, kaempferol, and quercetin) and terpene trilactones (ginkgolides A, B, C, and bilobalide) that aid GBEs' neutralizing effect against radiation and toxins by acting independently or synergistically. This will serve as a reference for the functional food, cosmetic, and pharmaceutical industries worldwide.

Preventive Effects of Ginkgo-Extract EGb 761® on Noise Trauma-Induced Cochlear Synaptopathy

Noise trauma-induced loss of ribbon synapses at the inner hair cells (IHC) of the cochlea may lead to hearing loss (HL), resulting in tinnitus. We are convinced that a successful and sustainable therapy of tinnitus has to treat both symptom and cause. One of these causes may be the mentioned loss of ribbon synapses at the IHC of the cochlea. In this study, we investigated the possible preventive and curative effects of the Ginkgo biloba extract EGb 761® on noise-induced synaptopathy, HL, and tinnitus development in Mongolian gerbils (Meriones unguiculatus). To this end, 37 male animals received EGb 761® or placebo orally 3 weeks before (16 animals) or after (21 animals) a monaural acoustic noise trauma (2 kHz, 115 dB SPL, 75 min). Animals' hearing thresholds were determined by auditory brainstem response (ABR) audiometry. A possible tinnitus percept was assessed by the gap prepulse inhibition acoustic startle reflex (GPIAS) response paradigm. Synaptopathy was quantified by cochlear immunofluorescence histology, counting the ribbon synapses of 15 IHCs at 11 different cochlear frequency locations per ear. We found a clear preventive effect of EGb 761® on ribbon synapse numbers with the surprising result of a significant increase in synaptic innervation on the trauma side relative to placebo-treated animals. Consequently, animals treated with EGb 761® before noise trauma did not develop a significant HL and were also less affected by tinnitus compared to placebo-treated animals. On the other hand, we did not see a curative effect (EGb 761® treatment after noise trauma) of the extract on ribbon synapse numbers and, consequently, a significant HL and no difference in tinnitus development compared to the placebo-treated animals. Taken together, EGb 761® prevented noise-induced HL and tinnitus by protecting from noise trauma-induced cochlear ribbon synapse loss; however, in our model, it did not restore lost ribbon synapses.

Pharmacologic treatments in preclinical tinnitus models with special focus on Ginkgo biloba leaf extract EGb 761®

Tinnitus is defined as the perception of sound in the absence of external acoustic stimuli. Frequent comorbidities or associated factors are depression, anxiety, concentration problems, insomnia, resignation, helplessness, headache, bruxism, or social isolation, just to name a few. Although many therapeutic approaches have already been tested with varying success, there still is no cure available for tinnitus. The search for an effective treatment has been hampered by the fact that the mechanisms of tinnitus development are still not fully understood, although several models are available and discussed in this review. Our review will give a brief overview about preclinical models, presenting the heterogeneity of tinnitus sub-types depending on the different inner ear and brain structures involved in tinnitus etiology and pathogenesis. Based on these models we introduce the different target structures and transmitter systems implicated in tinnitus development and provide an extensive overview on preclinical drug-based therapeutic approaches that have been explored in various animal models. As the special extract from Ginkgo biloba leaves EGb 761® has been the most widely tested drug in both non-clinical tinnitus models as well as in clinical trials, a special focus will be given to EGb 761®. The efficacy of terpene lactones, flavone glycosides and proanthocyanidines with their distinct contribution to the overall efficacy profile of the multi-constituent drug EGb 761® will be discussed.

The Role of Food Supplementation in Microcirculation-A Comprehensive Review

(1) Background: Cardiovascular disease (CVD) is a major public health concern worldwide and a key cause of morbidity and mortality in developed countries. Accumulating evidence shows that several CVD forms are characterized by significant microcirculatory dysfunction, which may both cause and be caused by macrovascular disease, often preceding clinical manifestations by several years. Therefore, interest in exploring food supplements to prevent and restore microcirculation has grown. Given the continuous need to expand the available therapeutic arsenal for CVD, the food supplements market has recently grown and is expected to continue growing. (2) Methods: We provide an authoritative up-to-date comprehensive review of the impact of food supplementation on microcirculation by analyzing the European and American legal food supplements framework and the importance of food safety/food quality in this industry. We review the main literature about food bioactive compounds with a focus on microcirculation and some main food supplements with proven benefits. (3) Results: Despite a lack of scientific evidence, diet and microcirculatory function are clearly connected. The main food supplement examples in the literature with potential beneficial effects on microcirculation are: Ruscus aculeatus L., Centella asiatica L., Ginkgo biloba L., Salvia miltiorrhiza Bunge, Crataegus spp., Ginseng, Mangifera indica L., Aesculus hippocastanum L., Hamamelis virginiana L., and Vitis vinifera L. (4) Conclusions: Further clinical trials are necessary to better explore the effects of these food supplements.

Combining Cochlear Analysis and Auditory Evoked Potentials in a Beluga Whale With High-Frequency Hearing Loss

Correlations between inner ear morphology and auditory sensitivity in the same individual are extremely difficult to obtain for stranded cetaceans. Animals in captivity and rehabilitation offer the opportunity to combine several techniques to study the auditory system and cases of hearing impairment in a controlled environment. Morphologic and auditory findings from two beluga whales (Delphinapterus leucas) in managed care are presented. Cochlear analysis of a 21-year-old beluga whale showed bilateral high-frequency hearing loss. Specifically, scanning electron microscopy of the left ear revealed sensory cell death in the first 4.9 mm of the base of the cochlea with scar formation. Immunofluorescence microscopy of the right ear confirmed the absence of hair cells and type I afferent innervation in the first 6.6 mm of the base of the cochlea, most likely due to an ischemia. Auditory evoked potentials (AEPs) measured 1.5 years prior this beluga's death showed a generalized hearing loss, being more pronounced in the high frequencies. This individual might have had a mixed hearing loss that would explain the generalized hearing impairment. Conversely, based on AEP evaluation, her mother had normal hearing and subsequent cochlear analysis did not feature any apparent sensorineural pathology. This is believed to be the first study to compare two cochlear analysis techniques and hearing sensitivity measurements from AEPs in cetaceans. The ability to combine morphological and auditory data is crucial to validate predictions of cochlear frequency maps based on morphological features. In addition, our study shows that these three complementary analysis techniques lead to comparable results, thus improving our understanding of how hearing impairment can be detected in stranding cases.

Clinical randomized trial study of hearing aids effectiveness in association with Ginkgo biloba extract (EGb 761) on tinnitus improvement

Introduction

Tinnitus is defined as the perception of sound without its actual presence in the environment. It has been the subject of a great number of studies, especially considering its consequences on patient's quality of life.

Objective

This study aimed to investigate the effect of hearing aids and/or Ginkgo biloba extract EGb 761 on tinnitus in patients with hearing loss.

Methods

This is a trial randomized-controlled treatment, parallel, double-blind, with three-arm. Thirty-three adults subjects were divided into three groups: group 1 — subjects undergoing drug therapy with Ginkgo biloba extract EGb 761; group 2 — individuals fitted with digital hearing aids; group 3 — individuals submitted to drug therapy with Ginkgo biloba extract EGb 761 and using hearing aids. The tinnitus handicap inventory and visual analogue scale were used to evaluate self-perception of tinnitus loudness and severity before treatment and 90 days after treatment.

Results

This study demonstrated a significant correlation between tinnitus handicap inventory and visual analogue scale, before and after treatment. We observed a significant improvement in self-perception of tinnitus loudness and severity after 90 days of treatment with Ginkgo biloba extract EGb 761 and/or hearing aids. No correlation was found between tinnitus onset time and self-perception of tinnitus loudness and severity. Hearing aids were more effective in patients with a shorter tinnitus onset time and Ginkgo biloba extract was effective regardless of tinnitus duration.

Conclusions

It was possible to prove the effectiveness of the hearing aids and/or Ginkgo biloba extract EGb 761 treatment, which shows success in the control of tinnitus contributing to the improvement of this symptom.

Lipopolysaccharide disrupts the cochlear blood-labyrinth barrier by activating perivascular resident macrophages and up-regulating MMP-9

OBJECTIVE

To determine the distribution of perivascularresident macrophages (PVMs) in BLB and their relationship with capillaries, and to explore the possible mechanisms responsible for lipopolysaccharide (LPS)-induced activation of PVMs and the breakdown of BLB.

METHODS

Adult Balb/c mice were either trans-tympanically injected with LPS, or mock-treated. Auditory brainstem response was tested before and 48 h after treatments. Distribution of pericytes, PVMs and capillaries was analyzed by immunohistochemical staining, and BLB permeability was estimated by FITC-dextran leakage assay. Ultrastructure of stria vascularis was examined by transmission electron microscope. Protein and mRNA level of matrix metallopeptidase 9 (MMP-9), zona occludens-1 (ZO-1), interleukin-33 (IL-33) and its receptor suppression of tumorigenicity 2 (ST2) was measured by IHC and qRT-PCR.

RESULTS

Unlike pericytes that surround one capillary, PVMs branched to connect with more than one capillary. LPS caused hearing loss in mice. Following LPS challenge, cochleae showed vascular leakage in stria vascularis, and PVMs presented morphological changes including reduced contact with capillaries. TEM revealed a reduced number of tight junction contact points between endothelial cells and a wider space between PVMs, pericytes and endothelial cells. The mRNA and protein levels of MMP-9 and ST2 in stria vascularis were up-regulated, while ZO-1 were down-regulated after exposure to LPS.

CONCLUSIONS

Our results suggest that PVMs may play a more significant role than pericytes in maintaining the integrity of BLB. Our findings also reveal a possible mechanism contributing to LPS-induced activation of PVMs, breakdown of BLB and hearing loss.

Protective effects of Ginkgo biloba L. against natural toxins, chemical toxicities, and radiation: A comprehensive review

Nowadays in our developing and industrial world, humans' health or even their life is threatened by exposure to poisons. In this situation, detecting a protective compound could be helpful and interesting. In the present article, we collected and reviewed all studies, which have been conducted so far about the protective effects of Ginkgo biloba L. (GB), one of the most ancient medicinal tree species, against toxicities induced by chemical toxic agents, natural toxins, and also radiation. In overall, investigations showed that GB exerts the antioxidant, antiinflammatory, antiapoptotic, and antigenotoxicity effects in different toxicities. There are also some special mechanisms about its protective effects against some specific toxic agents, such as acetylcholine esterase inhibition in the aluminium neurotoxicity or membrane-bond phosphodiesterase activation in the triethyltin toxicity. Ginkgolide A was the most investigated active ingredient of G. biloba leaf extract as a protective compound against toxicities, which had the similar effects of total extract. A few clinical studies have been conducted in this field, which demonstrated the beneficial effects of GB against toxic agents. However, the promising effects of this valuable herbal extract will practically remain useless without carrying out more clinical studies and proving its effects on human beings.

[Tanakan as a multimodal cytoprotective factor in general medicine (part II)]

The second section of the review provides an update of the data on mechanisms of action of a standardized extract of Ginkgo biloba EGb761® (tanakan) and its efficacy in treatment of depression, pain, complications of diabetes, Parkinson disease, tinnitus and dizziness, reproductive dysfunction. Updated data enable to use EGb761® (tanakan) as a highly-effective cytoprotective agent in treatment of cardiovascular, degenerative and metabolic diseases of the nervous system, inner ear disturbances (tinnitus), dysfunction of reproductive system as well as in prevention and treatment of stress-induced disorders.