Probiotic supplementation alleviates absence seizures and anxiety- and depression-like behavior in WAG/Rij rat by increasing neurotrophic factors and decreasing proinflammatory cytokines

Oral administration of bacterial probiotics improves Helicobacter pylori-induced memory impairment in rats: Insights from behavioral and biochemical investigations

There are numerous evidence supporting the association between Helicobacter pylori (H. pylori) infection and the occurrence of cognitive deficits in humans. In this regard, treatment of H. pylori infection has been suggested as an effective strategy to decelerate the neurodegenerative processes of memory deficits in AD patients. Numerous studies support the beneficial effects of probiotics on various pathological conditions, particularly cognitive deficits, however, this concern has not been addressed in relation to the memory impairment induced by H. pylori infection. In the present study, we aimed to reveal whether oral administration of two bacterial probiotics (including Lactobacillus rhamnosus and Lactobacillus plantarum), could ameliorate H. pylori-induced memory deficits at behavioral level in rats. Besides, cellular mechanisms were investigated by biochemical methods to find out how probiotic effects are mediated in hippocampal circuitry. Male Wistar rats were infected by H. pylori for 3 consecutive days, then probiotic treatment was done for the next 3 days and after a drug-free period (12 days), animals were assessed by Morris Water Maze and Novel Object Recognition tests. Finally, rats were euthanized by CO2 and hippocampal tissues were excised for biochemical measurements. Results indicated that H. pylori infection markedly impairs memory function in rats which is associated with alterations of oxidative, inflammatory, neurotrophic, and cholinergic markers. Interestingly, treatment with either of the probiotics alone or in combination, significantly improved the H. pylori-induced memory deficits and this was associated with restoration of balance in biochemical factors within the hippocampal neurons.

Effect of dietary supplementation with Lactobacillus helveticus R0052 on seizure thresholds and antiseizure potency of sodium valproate in mice

OBJECTIVE

Both animal and human studies, though limited, showed that multi-strain probiotic supplementation may reduce the number of seizures and/or seizure severity. Here, we evaluated the effect of a single strain probiotic supplementation on seizure susceptibility, antiseizure efficacy of sodium valproate, and several behavioral parameters in mice.

METHODS

Lactobacillus helveticus R0052 was given orally for 28 days. Its influence on seizure thresholds was evaluated in the ivPTZ- and electrically-induced seizure tests. The effect on the antiseizure potency of valproate was assessed in the scPTZ test. We also investigated the effects of probiotic supplementation on anxiety-related behavior (in the elevated plus maze and light/dark box tests), motor coordination (in the accelerating rotarod test), neuromuscular strength (in the grip-strength test), and spontaneous locomotor activity. Serum and brain concentrations of valproate as well as cecal contents of SCFAs and lactate were determined using HPLC method.

RESULTS

L. helveticus R0052 significantly increased the threshold for the 6 Hz-induced psychomotor seizure. There was also a slight increase in the threshold for myoclonic and clonic seizure in the ivPTZ test. L. helveticus R0052 did not affect the threshold for tonic seizures both in the maximal electroshock- and ivPTZ-induced seizure tests. No changes in the antiseizure potency of valproate against the PTZ-induced seizures were reported. Interestingly, L. helveticus R0052 increased valproate concentration in serum, but not in the brain. Moreover, L. helveticus R0052 did not produce any significant effects on anxiety-related behavior, motor coordination, neuromuscular strength, and locomotor activity. L. helveticus R0052 supplementation resulted in increased concentrations of total SCFAs, acetate, and butyrate.

CONCLUSIONS

Altogether, this study shows that a single-strain probiotic - L. helveticus R0052 may decrease seizure susceptibility and this effect can be mediated, at least in part, by increased production of SCFAs. In addition, L. helveticus R0052 may affect bioavailability of valproate, which warrants further investigations.

MiR-182-5p: A Novel Biomarker in the Treatment of Depression in CSDS-Induced Mice

BACKGROUND

Depression is a neuropsychiatric disease with a high disability rate and mainly caused by the chronic stress or genetic factors. There is increasing evidence that microRNAs (miRNAs) play a critical role in the pathogenesis of depression. However, the underlying molecular mechanism for the pathophysiology of depression of miRNA remains entirely unclear so far.

METHODS

We first established a chronic social defeat stress (CSDS) mice model of depression, and depression-like behaviors of mice were evaluated by a series of behavioral tests. Next, we detected several abundantly expressive miRNAs suggested in previous reports to be involved in depression and found miR-182-5p was selected as a candidate for analysis in the hippocampus. Then western blotting and immunofluorescence were used together to examine whether adeno-associated virus (AAV)-siR-182-5p treatment alleviated chronic stress-induced decrease in hippocampal Akt/GSK3β/cAMP-response element binding protein (CREB) signaling pathway and increase in neurogenesis impairment and neuroinflammation. Furthermore, CREB inhibitor was adopted to examine if blockade of Akt/GSK3β/CREB signaling pathway abolished the antidepressant actions of AAV-siR-182-5p in mice.

RESULTS

Knockdown of miR-182-5p alleviated depression-like behaviors and impaired neurogenesis of CSDS-induced mice. Intriguingly, the usage of agomiR-182-5p produced significant increases in immobility times and aggravated neuronal neurogenesis damage of mice. More importantly, it suggested that 666-15 blocked the reversal effects of AAV-siR-182-5p on the CSDS-induced depressive-like behaviors in behavioral testing and neuronal neurogenesis within hippocampus of mice.

CONCLUSIONS

These findings indicated that hippocampal miR-182-5p/Akt/GSK3β/CREB signaling pathway participated in the pathogenesis of depression, and it might give more opportunities for new drug developments based on the miRNA target in the clinic.

Insights into the Current and Possible Future Use of Opioid Antagonists in Relation to Opioid-Induced Constipation and Dysbiosis

Opioid receptor agonists, particularly those that activate µ-opioid receptors (MORs), are essential analgesic agents for acute or chronic mild to severe pain treatment. However, their use has raised concerns including, among others, intestinal dysbiosis. In addition, growing data on constipation-evoked intestinal dysbiosis have been reported. Opioid-induced constipation (OIC) creates an obstacle to continuing treatment with opioid analgesics. When non-opioid therapies fail to overcome the OIC, opioid antagonists with peripheral, fast first-pass metabolism, and gastrointestinal localized effects remain the drug of choice for OIC, which are discussed here. At first glance, their use seems to only be restricted to constipation, however, recent data on OIC-related dysbiosis and its contribution to the appearance of several opioid side effects has garnered a great of attention from researchers. Peripheral MORs have also been considered as a future target for opioid analgesics with limited central side effects. The properties of MOR antagonists counteracting OIC, and with limited influence on central and possibly peripheral MOR-mediated antinociception, will be highlighted. A new concept is also proposed for developing gut-selective MOR antagonists to treat or restore OIC while keeping peripheral antinociception unaffected. The impact of opioid antagonists on OIC in relation to changes in the gut microbiome is included.

Effects of probiotics on GABA/glutamate and oxidative stress in PTZ- induced acute seizure model in rats

Studies conducted in recent years have indicated a relationship between epilepsy and gut microbiota. Ion channels, excitatory/inhibitory balance and regulatory systems play a role in the pathophysiology of epilepsy. In addition, gut dysbiosis is also involved in the pathophysiology of epilepsy. This research investigated the impacts of probiotic mixture on epileptic seizures, Gamma aminobutyric acid (GABA), glutamate, and TAS and TOS levels in hippocampal tissue in the PTZ-induced acute seizure model in rats. Four groups were formed with male Wistar albino rats. The first and second groups were given 1 ml/day saline solution, and the other groups were given 0.05 mg/1 ml/day vehicle or 109cfu/1 ml/day probiotic supplementation, respectively via gavage for 21 days. A single-dose PTZ (45 mg/kg) was administered to induce seizure. The stages of seizure were analyzed according to the Racine scale. While ELISA was used to determine GABA and glutamate levels in the hippocampus, an automated colorimetric method was utilized to measure oxidant/antioxidant biomarkers. It was found that by delaying the first myoclonic jerk (FMJ), and the onset of the generalized tonic-clonic seizures, the probiotic mixture demonstrated anticonvulsant effects against seizures. The probiotic mixture was found to increase the inhibitory neurotransmitter GABA. It was also found to decrease TOS levels and increase TAS concentration. The findings of this study showed that probiotic mixture reduced oxidative stress with its positive effects against PTZ-induced epileptic seizures. Further studies are needed to reveal potentially related mechanisms.

Beneficial Effects of Probiotic Bifidobacterium longum in a Lithium-Pilocarpine Model of Temporal Lobe Epilepsy in Rats

Epilepsy is a challenging brain disorder that is often difficult to treat with conventional therapies. The gut microbiota has been shown to play an important role in the development of neuropsychiatric disorders, including epilepsy. In this study, the effects of Bifidobacterium longum, a probiotic, on inflammation, neuronal degeneration, and behavior are evaluated in a lithium-pilocarpine model of temporal lobe epilepsy (TLE) induced in young adult rats. B. longum was administered orally at a dose of 10⁹ CFU/rat for 30 days after pilocarpine injection. The results show that B. longum treatment has beneficial effects on the TLE-induced changes in anxiety levels, neuronal death in the amygdala, and body weight recovery. In addition, B. longum increased the expression of anti-inflammatory and neuroprotective genes, such as Il1rn and Pparg. However, the probiotic had little effect on TLE-induced astrogliosis and microgliosis and did not reduce neuronal death in the hippocampus and temporal cortex. The study suggests that B. longum may have a beneficial effect on TLE and may provide valuable insights into the role of gut bacteria in epileptogenesis. In addition, the results show that B. longum may be a promising drug for the comprehensive treatment of epilepsy.

A Microbial-Based Approach to Mental Health: The Potential of Probiotics in the Treatment of Depression

Probiotics are currently the subject of intensive research pursuits and also represent a multi-billion-dollar global industry given their vast potential to improve human health. In addition, mental health represents a key domain of healthcare, which currently has limited, adverse-effect prone treatment options, and probiotics may hold the potential to be a novel, customizable treatment for depression. Clinical depression is a common, potentially debilitating condition that may be amenable to a precision psychiatry-based approach utilizing probiotics. Although our understanding has not yet reached a sufficient level, this could be a therapeutic approach that can be tailored for specific individuals with their own unique set of characteristics and health issues. Scientifically, the use of probiotics as a treatment for depression has a valid basis rooted in the microbiota-gut-brain axis (MGBA) mechanisms, which play a role in the pathophysiology of depression. In theory, probiotics appear to be ideal as adjunct therapeutics for major depressive disorder (MDD) and as stand-alone therapeutics for mild MDD and may potentially revolutionize the treatment of depressive disorders. Although there is a wide range of probiotics and an almost limitless range of therapeutic combinations, this review aims to narrow the focus to the most widely commercialized and studied strains, namely Lactobacillus and Bifidobacterium, and to bring together the arguments for their usage in patients with major depressive disorder (MDD). Clinicians, scientists, and industrialists are critical stakeholders in exploring this groundbreaking concept.

Interactions Between Antidepressants and Intestinal Microbiota

The microbiota-gut-brain axis has been shown to influence human health and diseases, including depression. The interactions between drugs and intestinal microbiota are complex and highly relevant to treat diseases. Studies have shown an interaction between antidepressants and intestinal microbiota. Antidepressants may alter the abundance and composition of intestinal microbiota, which are closely related to the treatment outcomes of depression. Intestinal microbiota can influence the metabolism of antidepressants to change their availability (e.g., tryptophan can be metabolized to kynurenine by intestinal microbiota) and regulate their absorption by affecting intestinal permeability. In addition, the permeability of the blood-brain barrier can be altered by intestinal microbiota, influencing antidepressants to reach the central nervous system. Bioaccumulation is also a type of drug-microbiota interaction, which means bacteria accumulate drugs without biotransformation. These findings imply that it is important to consider intestinal microbiota when evaluating antidepressant therapy regimens and that intestinal microbiota can be a potential target for depression treatment.

Possible Effects and Mechanisms of Dietary Natural Products and Nutrients on Depression and Anxiety: A Narrative Review

Depression and anxiety are severe public health problems and have attracted more and more attention from researchers of food science and nutrition. Dietary natural products and nutrients, such as fish, coffee, tea, n-3 PUFA, lycopene, and dietary fiber, could play a vital role in the prevention and management of these diseases. The potential mechanisms of action mainly include inhibiting inflammation, ameliorating oxidative stress, modulating the microbiota-gut-brain axis, suppressing hypothalamic-pituitary-adrenal axis hyperactivity, and regulating the levels of monoamine neurotransmitters. In this narrative review, we summarize the most recent advancements regarding the effects of dietary natural products and nutrients on depression and anxiety, and their underlying mechanisms are discussed. We hope that this paper can provide a better understanding of the anti-depressive and anxiolytic action of dietary natural products, and that it is also helpful for developing dietary natural products for functional food, dietary supplements, or auxiliary agents for the prevention and management of these diseases.

Role of Short Chain Fatty Acids in Epilepsy and Potential Benefits of Probiotics and Prebiotics: Targeting “Health” of Epileptic Patients

The WHO’s definition of health transcends the mere absence of disease, emphasizing physical, mental, and social well-being. As this perspective is being increasingly applied to the management of chronic diseases, research on gut microbiota (GM) is surging, with a focus on its potential for persistent and noninvasive dietary therapeutics. In patients with epilepsy (PWE), a chronic lack of seizure control along with often neglected psychiatric comorbidities greatly disrupt the quality of life. Evidence shows that GM-derived short chain fatty acids (SCFAs) may impact seizure susceptibility through modulating (1) excitatory/inhibitory neurotransmitters, (2) oxidative stress and neuroinflammation, and (3) psychosocial stress. These functions are also connected to shared pathologies of epilepsy and its two most common psychiatric consequences: depression and anxiety. As the enhancement of SCFA production is enabled through direct administration, as well as probiotics and prebiotics, related dietary treatments may exert antiseizure effects. This paper explores the potential roles of SCFAs in the context of seizure control and its mental comorbidities, while analyzing existing studies on the effects of pro/prebiotics on epilepsy. Based on currently available data, this study aims to interpret the role of SCFAs in epileptic treatment, extending beyond the absence of seizures to target the health of PWE.