Impact of interval training with probiotic (L. plantarum / Bifidobacterium bifidum) on passive avoidance test, ChAT and BDNF in the hippocampus of rats with Alzheimer's disease

Optimization of fermentation conditions for enhanced acetylcholine and biomass production of Lactiplantibacillus plantarum AM2 using the Taguchi approach

This study aimed to optimize the fermentation conditions and medium composition for maximum acetylcholine (ACh) and biomass production by Lactiplantibacillus plantarum AM2 using the Taguchi array design, which enables efficient identification of influential variables through minimal experimental runs. Seven key factors were evaluated: beef extract, peptone, yeast extract, glucose, pH, agitation rate, and inoculation size. The optimization process identified the most significant variables influencing ACh and biomass production, with beef extract and peptone being critical for ACh synthesis, while inoculation size was a critical determinant of biomass yield. The optimal conditions for ACh production were determined as beef extract (11 g/l), peptone (40 g/l), yeast extract (5 g/l), glucose (20 g/l), pH 5.7, no agitation, and 1% (v/v) inoculation size, resulting in a predicted ACh concentration of 490.83 pg/ml and an experimental value of 495.8 pg/ml. For biomass production, the optimal conditions were beef extract (8 g/l), peptone (10 g/l), yeast extract (20 g/l), glucose (35 g/l), pH 6.6, agitation at 150 rpm, and 4% (v/v) inoculation size, yielding a predicted biomass of 20.58 g/l and an experimental value of 21.3 g/l. The optimized conditions significantly improved ACh production (6.32-fold) and biomass production (4.56-fold) compared to basal conditions. These findings highlight the efficiency of the Taguchi approach in enhancing the production of ACh and biomass, providing insights into the functional niche of Lactiplantibacillus plantarum AM2 for potential industrial applications and its use in a symbiotic form.

Probiotics and Prebiotics: Meeting Dietary Requirements for Optimal Health and Planetary Sustainability

Probiotics and prebiotics are valuable in enhancing human health and fostering sustainable development. This review focuses on the role of probiotics and prebiotics at all stages of life to promote nutrient absorption, boost immunity, and support healthy aging by mitigating cognitive decline and chronic disease. Health and environmental sustainability are deeply connected, making probiotics and prebiotics promising tools for promoting well-being and achieving global sustainability goals. In addition to health, probiotics and prebiotics contribute to sustainable development by optimizing agricultural byproducts, reducing reliance on antibiotics in animal feed, lowering greenhouse gas emissions, and supporting environmental protection. Future research should focus on personalizing treatments, improving bioavailability, and expanding applications to effectively address global health and the sustainable development goals.

The Brain-Gut-Bone Axis in Neurodegenerative Diseases: Insights, Challenges, and Future Prospects

Neurodegenerative diseases are global health challenges characterized by the progressive degeneration of nerve cells, leading to cognitive and motor impairments. The brain-gut-bone axis, a complex network that modulates multiple physiological systems, has gained increasing attention owing to its profound effects on the occurrence and development of neurodegenerative diseases. No comprehensive review has been conducted to clarify the triangular relationship involving the brain-gut-bone axis and its potential for innovative therapies for neurodegenerative disorders. In light of this, a new perspective is aimed to propose on the interplay between the brain, gut, and bone systems, highlighting the potential of their dynamic communication in neurodegenerative diseases, as they modulate multiple physiological systems, including the nervous, immune, endocrine, and metabolic systems. Therapeutic strategies for maintaining the balance of the axis, including brain health regulation, intestinal microbiota regulation, and improving skeletal health, are also explored. The intricate physiological interactions within the brain-gut-bone axis pose a challenge in the development of effective treatments that can comprehensively target this system. Furthermore, the safety of these treatments requires further evaluation. This review offers a novel insights and strategies for the prevention and treatment of neurodegenerative diseases, which have important implications for clinical practice and patient well-being.

Microbiota-Gut-Brain Axis Dysregulation in Alzheimer's Disease: Multi-Pathway Effects and Therapeutic Potential

An essential regulator of neurodegenerative conditions like Alzheimer's disease (AD) is the gut microbiota. Alterations in intestinal permeability brought on by gut microbiota dysregulation encourage neuroinflammation, central immune dysregulation, and peripheral immunological dysregulation in AD, as well as hasten aberrant protein aggregation and neuronal death in the brain. However, it is unclear how the gut microbiota transmits information to the brain and how it influences brain cognition and function. In this review, we summarized the multiple pathways involved in the gut microbiome in AD and provided detailed treatment strategies based on the gut microbiome. Based on these observations, this review also discusses the problems, challenges, and strategies to address current therapeutic strategies.

Oxidized/unmodified-polyethylene microplastics neurotoxicity in mice: Perspective from microbiota-gut-brain axis

Microplastics (MPs) are inevitably oxidized in the environment, and their potential toxicity to organisms has attracted wide attention. However, the neurotoxicity and mechanism of oxidized polyethylene (Ox-PE) MPs to organisms remain unclear. Herein, we prepared oxidized low-density polyethylene (Ox-LDPE) and established a model of MPs exposure by continuously orally gavage of C57BL/6 J mice with LDPE-MPs/Ox-LDPE-MPs for 28 days with or without oral administration of Lactobacillus plantarum DP189 and galactooligosaccharides (DP189&GOS). The experimental results indicated that LDPE-MPs or Ox-LDPE-MPs caused several adverse effects in mice, mainly manifested by behavioral changes, disruption of the intestinal and blood-brain barrier (BBB), and simultaneous oxidative stress, inflammatory reactions, and pathological damage in the brain and intestines. Brain transcriptomic analysis revealed that the cholinergic synaptic signaling pathways, which affect cognitive function, were significantly disrupted after exposure to LDPE-MPs or Ox-LDPE-MPs. Real-time quantitative polymerase chain reaction and Western Blotting results further demonstrated that the critical genes (Slc5a7, Chat and Slc18a3) and proteins (Chat and Slc18a3) in the cholinergic synaptic signaling pathway were significantly down-regulated after exposure to LDPE-MPs or Ox-LDPE-MPs. These alterations lead to reduced acetylcholine concentration, which causes cognitive dysfunction in mice. Importantly, the DP189&GOS interventions effectively mitigated the MPs-induced cognitive dysfunction and intestinal microbiota alteration, improved intestinal and BBB integrity, attenuated the oxidative stress and inflammatory response, and also saw a rebound in the release of acetylcholine. These results indicated that LDPE-MPs and Ox-LDPE-MPs exert neurotoxic effects on mice by inducing oxidative stress, inflammatory responses, and dysregulation of cholinergic signaling pathways in the mouse brain. That probiotic supplementation is effective in attenuating MPs-induced neurotoxicity in mice. Overall, this study reveals the potential mechanisms of neurotoxicity of LDPE-MPs and Ox-LDPE-MPs on mice and their improvement measures, necessary to assess the potential risks of plastic contaminants to human health.

Preparation and characterization of brain-targeted polymeric nanocarriers (Frankincense-PMBN-lactoferrin) and in-vivo evaluation on an Alzheimer's disease-like rat model induced by scopolamine

Experiments have demonstrated that frankincense may offer protection against scopolamine-induced Alzheimer's disease by mitigating cholinergic dysfunction and inhibiting inflammatory mediators. Nevertheless, its instability and limited water solubility lead to diminished medicinal efficacy. In this study, we utilized PMBN (poly [MPC-co-(BMA)-co-(MEONP)]) as a nanocarrier for targeted brain drug delivery of frankincense, employing lactoferrin as a ligand for precise targeting. Characterization of nanoparticle properties was conducted through FTIR and FESEM analysis, and the in-vitro drug release percentage from the nanoparticles was quantified. To induce Alzheimer's-like dementia in rats, scopolamine was intraperitoneally administered at a dose of 1 mg/kg/day for 14 days. Subsequently, behavioral assessments (Y-maze, passive avoidance test, tail suspension test) were performed, followed by evaluations of acetylcholinesterase (AChE), reduced glutathione (GSH), catalase (CAT), and brain histopathology at the conclusion of the treatment period. The results revealed that the nanoparticles had a size of 106.6 nm and a zeta potential of -3.8 mV. The maximum release of frankincense in the PBS environment from PMBN nanoparticles was 18.2 %, in accordance with the Peppas model. Behavioral tests indicated that targeted drug nanoparticles (F-PMBN-Lf) exhibited the capability to alleviate stress and depression while enhancing short-term memory in scopolamine-induced animals. Additionally, F-PMBN-Lf counteracted the scopolamine-induced elevation of AChE activity and GSH levels. However, it resulted in decreased activity of the antioxidant enzyme CAT compared to the scopolamine group. Histological analysis of brain tissue suggested that F-PMBN-Lf exerted a notable neuroprotective effect, preserving neuronal cells in contrast to the scopolamine-induced group. It appears that the polymer nanoparticles containing this plant extract have introduced a novel neuroprotective approach for the treatment of Alzheimer's disease.

Exercise Intervention for Alzheimer's Disease: Unraveling Neurobiological Mechanisms and Assessing Effects

Alzheimer's disease (AD) is a progressive neurodegenerative disease and a major cause of age-related dementia, characterized by cognitive dysfunction and memory impairment. The underlying causes include the accumulation of beta-amyloid protein (Aβ) in the brain, abnormal phosphorylation, and aggregation of tau protein within nerve cells, as well as neuronal damage and death. Currently, there is no cure for AD with drug therapy. Non-pharmacological interventions such as exercise have been widely used to treat AD, but the specific molecular and biological mechanisms are not well understood. In this narrative review, we integrate the biology of AD and summarize the knowledge of the molecular, neural, and physiological mechanisms underlying exercise-induced improvements in AD progression. We discuss various exercise interventions used in AD and show that exercise directly or indirectly affects the brain by regulating crosstalk mechanisms between peripheral organs and the brain, including "bone-brain crosstalk", "muscle-brain crosstalk", and "gut-brain crosstalk". We also summarize the potential role of artificial intelligence and neuroimaging technologies in exercise interventions for AD. We emphasize that moderate-intensity, regular, long-term exercise may improve the progression of Alzheimer's disease through various molecular and biological pathways, with multimodal exercise providing greater benefits. Through in-depth exploration of the molecular and biological mechanisms and effects of exercise interventions in improving AD progression, this review aims to contribute to the existing knowledge base and provide insights into new therapeutic strategies for managing AD.

Ameliorative effects of pine nut peptide-zinc chelate (Korean pine) on a mouse model of Alzheimer's disease

In this study, 50 SD adult male mice were used to create an Alzheimer's disease model. The mice's learning and memory abilities were evaluated using an eight-arm radial maze experiment, and changes in body weight and food intake were noted. This helped to better validate the improvement of Alzheimer's disease caused by pine nut peptide-zinc chelate (Korean pine). For a more thorough investigation, mice's brains were dissected, Endogenous mercaptan antioxidants (enzymes), which are markers of brain tissue, were assessed, and mouse gut flora was analyzed. The findings demonstrated that pine nut peptide-zinc chelate (Korean pine) can improve learning and memory, stop brain aging and damage, and control gut flora in mice. It may exert its effects by ameliorating decreased AChE levels and increased ChAT levels in the central cholinergic system, endogenous thiol antioxidants (enzymes) in the cerebral cortex, and by controlling the bacterial flora in the gut.

Physical Exercise as Disease-Modifying Alternative against Alzheimer's Disease: A Gut-Muscle-Brain Partnership

Alzheimer's disease (AD) is a common cause of dementia characterized by neurodegenerative dysregulations, cognitive impairments, and neuropsychiatric symptoms. Physical exercise (PE) has emerged as a powerful tool for reducing chronic inflammation, improving overall health, and preventing cognitive decline. The connection between the immune system, gut microbiota (GM), and neuroinflammation highlights the role of the gut-brain axis in maintaining brain health and preventing neurodegenerative diseases. Neglected so far, PE has beneficial effects on microbial composition and diversity, thus providing the potential to alleviate neurological symptoms. There is bidirectional communication between the gut and muscle, with GM diversity modulation and short-chain fatty acid (SCFA) production affecting muscle metabolism and preservation, and muscle activity/exercise in turn inducing significant changes in GM composition, functionality, diversity, and SCFA production. This gut-muscle and muscle-gut interplay can then modulate cognition. For instance, irisin, an exercise-induced myokine, promotes neuroplasticity and cognitive function through BDNF signaling. Irisin and muscle-generated BDNF may mediate the positive effects of physical activity against some aspects of AD pathophysiology through the interaction of exercise with the gut microbial ecosystem, neural plasticity, anti-inflammatory signaling pathways, and neurogenesis. Understanding gut-muscle-brain interconnections hold promise for developing strategies to promote brain health, fight age-associated cognitive decline, and improve muscle health and longevity.

Concurrent high-intensity interval training and probiotic supplementation improve associative memory via increase in insulin sensitivity in ovariectomized rats

OBJECTIVES

Metabolic syndrome (MetS) is a serious concern among postmenopausal women which predisposes them to cardiovascular and cognitive disorders. Healthful diet and exercise training have been essential strategies to prevent the progress of MetS. The aim of this study was to evaluate the effect of supplementation with a native potential probiotic and high-intensity interval training (HIIT) for 8 weeks on retention of associative memory in rats with ovariectomy- induced metabolic syndrome.

METHOD

Thirty-two female ovariectomized Wistar rats were divided into four groups (n = 8/group): Control (OVX + Veh), exercise (OVX + Exe), probiotic (OVX + Pro), exercise with probiotic (OVX + Exe + Pro). One sham surgery group was included as a control group. Animals received 8 weeks interventions, and then were tested in a step through passive avoidance learning and memory paradigm, to assess long term memory. Then serum levels of adiponectin, insulin and glucose were measured by ELISA and colorimetry respectively. Data were analyzed by Kruskal-Wallis, Mann-Whitney and also One-way analysis of variance (ANOVA).

RESULTS

Eight weeks of HIIT and probiotic supplementation caused an increase in step through latency and shortening of total time spent in the dark compartment in OVX + Exe + Pro group compared with OVX + Veh group. Also significant increase in serum adiponectin levels, in parallel with a reduction in glucose, insulin and HOMA-IR were achieved by the group of OVX + Exe + Pro.

CONCLUSION

The present study indicates that HIIT combined with probiotics supplementation for 8 weeks effectively improves associative memory in MetS model of rats partly via improving insulin sensitivity and adiponectin level.

Therapeutic Prospect of New Probiotics in Neurodegenerative Diseases

Increasing clinical and preclinical evidence implicates gut microbiome (GM) dysbiosis as a key susceptibility factor for neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD). In recent years, neurodegenerative diseases have been viewed as being driven not solely by defects in the brain, and the role of GM in modulating central nervous system function via the gut-brain axis has attracted considerable interest. Encouraged by current GM research, the development of new probiotics may lead to tangible impacts on the treatment of neurodegenerative disorders. This review summarizes current understandings of GM composition and characteristics associated with neurodegenerative diseases and research demonstrations of key molecules from the GM that affect neurodegeneration. Furthermore, applications of new probiotics, such as Clostridium butyricum, Akkermansia muciniphila, Faecalibacterium prausnitzii, and Bacteroides fragilis, for the remediation of neurodegenerative diseases are discussed.

Microbiota-gut-brain axis and related therapeutics in Alzheimer's disease: prospects for multitherapy and inflammation control

Alzheimer's disease (AD) is the most common type of dementia in the elderly and causes neurodegeneration, leading to memory loss, behavioral disorder, and psychiatric impairment. One potential mechanism contributing to the pathogenesis of AD may be the imbalance in gut microbiota, local and systemic inflammation, and dysregulation of the microbiota-gut-brain axis (MGBA). Most of the AD drugs approved for clinical use today are symptomatic treatments that do not improve AD pathologic changes. As a result, researchers are exploring novel therapeutic modalities. Treatments involving the MGBA include antibiotics, probiotics, transplantation of fecal microbiota, botanical products, and others. However, single-treatment modalities are not as effective as expected, and a combination therapy is gaining momentum. The purpose of this review is to summarize recent advances in MGBA-related pathological mechanisms and treatment modalities in AD and to propose a new concept of combination therapy. "MGBA-based multitherapy" is an emerging view of treatment in which classic symptomatic treatments and MGBA-based therapeutic modalities are used in combination. Donepezil and memantine are two commonly used drugs in AD treatment. On the basis of the single/combined use of these two drugs, two/more additional drugs and treatment modalities that target the MGBA are chosen based on the characteristics of the patient's condition as an adjuvant treatment, as well as the maintenance of good lifestyle habits. "MGBA-based multitherapy" offers new insights for the treatment of cognitive impairment in AD patients and is expected to show good therapeutic results.

Recent developments in the probiotics as live biotherapeutic products (LBPs) as modulators of gut brain axis related neurological conditions

Probiotics have been defined as “living microorganisms that create health benefits in the host when taken in sufficient amounts. Recent developments in the understanding of the relationship between the microbiom and its host have shown evidence about the promising potential of probiotics to improve certain health problems. However, today, there are some confusions about traditional and new generation foods containing probiotics, naming and classifications of them in scientific studies and also their marketing. To clarify this confusion, the Food and Drug Administration (FDA) declared that it has made a new category definition called "live biotherapeutic products" (LBPs). Accordingly, the FDA has designated LBPs as “a biological product that: i)contains live organisms, such as bacteria; ii)is applicable to the prevention, treatment, or cure of a disease/condition of human beings; and iii) is not a vaccine”. The accumulated literature focused on LBPs to determine effective strains in health and disease, and often focused on obesity, diabetes, and certain diseases like inflammatory bowel disease (IBD).However, microbiome also play an important role in the pathogenesis of diseases that age day by day in the modern world via gut-brain axis. Herein, we discuss the novel roles of LBPs in some gut-brain axis related conditions in the light of recent studies. This article may be of interest to a broad readership including those interested in probiotics as LBPs, their health effects and safety, also gut-brain axis.

Neuroprotective Potential of HC070, a Potent TRPC5 Channel Inhibitor in Parkinson's Disease Models: A Behavioral and Mechanistic Study

Transient receptor potential canonical 5 (TRPC5) channels are predominantly expressed in the striatum and substantia nigra of the brain. These channels are permeable to calcium ions and are activated by oxidative stress. The physiological involvement of TRPC5 channels in temperature and mechanical sensation is well documented; however, evidence for their involvement in the pathophysiology of neurodegenerative disorders like Parkinson's disease (PD) is sparse. Thus, in the present study, the role of TRPC5 channels and their associated downstream signaling was elucidated in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/1-methyl-4-phenylpyridinium (MPTP/MPP⁺) model of PD. Bilateral intranigral administration of MPTP and 24 h MPP⁺ exposure were performed to induce PD in the Sprague-Dawley rats and SH-SY5Y cells, respectively. MPTP led to behavioral anomalies and TRPC5 overexpression accompanied by increased calcium influx, apoptosis, oxidative stress, and mitochondrial dysfunctions. In addition, tyrosine hydroxylase (TH) expression was significantly lower in the midbrain and substantia nigra compared to sham animals. Intraperitoneal administration of potent and selective TRPC5 inhibitor, HC070 (0.1 and 0.3 mg/kg) reversed the cognitive and motor deficits seen in MPTP-lesioned rats. It also restored the TH and TRPC5 expression both in the striatum and midbrain. Furthermore, in vitro and in vivo studies suggested improvements in mitochondrial health along with reduced oxidative stress, apoptosis, and calcium-mediated excitotoxicity. Together, these results showed that inhibition of TRPC5 channels plays a crucial part in the reversal of pathology in the MPTP/MPP⁺ model of Parkinson's disease.

Gut microbiota dysbiosis induced by polychlorinated biphenyl 126 contributes to increased brain proinflammatory cytokines: Landscapes from the gut-brain axis and fecal microbiota transplantation

The pathogenesis of brain inflammation induced by polychlorinated biphenyl 126 (PCB126) has not yet been fully illustrated. Growing evidence highlights the relevance of the microbiota-gut-brain axis in central nervous system (CNS) dysfunction. Therefore, we aimed to study the role of the gut microbiota in PCB126-induced proinflammatory cytokine increases in the mouse brain. The results showed that PCB126 exposure significantly disordered gut bacterial communities, resulting in the enrichment of gram-negative bacteria (e.g., Bacteroidetes and Proteobacteria), further leading to elevated levels of the gram-negative bacterial lipopolysaccharide (LPS). Subsequently, colonic toll-like receptor 4 (TLR-4) was activated by bacterial LPS, which promoted proinflammatory cytokine generation and inhibited tight junction (TJ) protein expression. Then, bacterial LPS translocated from the gut lumen into the blood circulation and reached the brain, triggering LPS/TLR-4-mediated increases in brain proinflammatory cytokines. Further analysis after fecal microbiota transplantation (FMT) suggested that the gut microbiota disturbance caused by PCB126 could induce elevated bacterial LPS and trigger TLR-4-mediated increases in proinflammatory cytokines in the brain. This study highlights the possibility that PCB126-induced gut microbiota disorder contributes to increased brain proinflammatory cytokines. These results provide a new perspective for identifying the toxicity mechanisms of PCB126 and open up the possibility of modulating the gut microbiota as a therapeutic target for CNS disease caused by environmental pollution.

Neurovascular Dysfunction in Diverse Communities With Health Disparities-Contributions to Dementia and Alzheimer's Disease

Alzheimer's disease and related dementias (ADRD) are an expanding worldwide crisis. In the absence of scientific breakthroughs, the global prevalence of ADRD will continue to increase as more people are living longer. Racial or ethnic minority groups have an increased risk and incidence of ADRD and have often been neglected by the scientific research community. There is mounting evidence that vascular insults in the brain can initiate a series of biological events leading to neurodegeneration, cognitive impairment, and ADRD. We are a group of researchers interested in developing and expanding ADRD research, with an emphasis on vascular contributions to dementia, to serve our local diverse community. Toward this goal, the primary objective of this review was to investigate and better understand health disparities in Alabama and the contributions of the social determinants of health to those disparities, particularly in the context of vascular dysfunction in ADRD. Here, we explain the neurovascular dysfunction associated with Alzheimer's disease (AD) as well as the intrinsic and extrinsic risk factors contributing to dysfunction of the neurovascular unit (NVU). Next, we ascertain ethnoregional health disparities of individuals living in Alabama, as well as relevant vascular risk factors linked to AD. We also discuss current pharmaceutical and non-pharmaceutical treatment options for neurovascular dysfunction, mild cognitive impairment (MCI) and AD, including relevant studies and ongoing clinical trials. Overall, individuals in Alabama are adversely affected by social and structural determinants of health leading to health disparities, driven by rurality, ethnic minority status, and lower socioeconomic status (SES). In general, these communities have limited access to healthcare and healthy food and other amenities resulting in decreased opportunities for early diagnosis of and pharmaceutical treatments for ADRD. Although this review is focused on the current state of health disparities of ADRD patients in Alabama, future studies must include diversity of race, ethnicity, and region to best be able to treat all individuals affected by ADRD.

Morais L. Convergent pathways of the gut microbiota-brain axis and neurodegenerative disorders

Recent research has been uncovering the role of the gut microbiota for brain health and disease. These studies highlight the role of gut microbiota on regulating brain function and behavior through immune, metabolic, and neuronal pathways. In this review we provide an overview of the gut microbiota axis pathways to lay the groundwork for upcoming sessions on the links between the gut microbiota and neurogenerative disorders. We also discuss how the gut microbiota may act as an intermediate factor between the host and the environment to mediate disease onset and neuropathology. Based on the current literature, we further examine the potential for different microbiota-based therapeutic strategies to prevent, to modify, or to halt the progress of neurodegeneration.

Fecal Microbiota Transplantation Derived from Alzheimer's Disease Mice Worsens Brain Trauma Outcomes in Wild-Type Controls

Traumatic brain injury (TBI) causes neuroinflammation and neurodegeneration, both of which increase the risk and accelerate the progression of Alzheimer's disease (AD). The gut microbiome is an essential modulator of the immune system, impacting the brain. AD has been related with reduced diversity and alterations in the community composition of the gut microbiota. This study aimed to determine whether the gut microbiota from AD mice exacerbates neurological deficits after TBI in control mice. We prepared fecal microbiota transplants from 18 to 24 month old 3×Tg-AD (FMT-AD) and from healthy control (FMT-young) mice. FMTs were administered orally to young control C57BL/6 (wild-type, WT) mice after they underwent controlled cortical impact (CCI) injury, as a model of TBI. Then, we characterized the microbiota composition of the fecal samples by full-length 16S rRNA gene sequencing analysis. We collected the blood, brain, and gut tissues for protein and immunohistochemical analysis. Our results showed that FMT-AD administration stimulates a higher relative abundance of the genus Muribaculum and a decrease in Lactobacillus johnsonii compared to FMT-young in WT mice. Furthermore, WT mice exhibited larger lesion, increased activated microglia/macrophages, and reduced motor recovery after FMT-AD compared to FMT-young one day after TBI. In summary, we observed gut microbiota from AD mice to have a detrimental effect and aggravate the neuroinflammatory response and neurological outcomes after TBI in young WT mice.

A Systematic Review on the Effects of Different Types of Probiotics in Animal Alzheimer's Disease Studies

Alzheimer's disease (AD) is a global public health priority as with aging populations, its prevalence is expected to rise even further in the future. The brain and gut are in close communication through immunological, nervous and hormonal routes, and therefore, probiotics are examined as an option to influence AD hallmarks, such as plaques, tangles, and low grade inflammation. This study aimed to provide an overview of the available animal evidence on the effect of different probiotics on gut microbiota composition, short chain fatty acids (SCFAs), inflammatory markers, Amyloid-β (Aβ), and cognitive functioning in AD animal models. A systematic literature search was performed in PubMed, SCOPUS, and APA PsychInfo. Articles were included up to May 2021. Inclusion criteria included a controlled animal study on probiotic supplementation and at least one of the abovementioned outcome variables. Of the eighteen studies, most were conducted in AD male mice models (n = 9). Probiotics of the genera Lactobacillus and Bifidobacterium were used most frequently. Probiotic administration increased species richness and/or bacterial richness in the gut microbiota, increased SCFAs levels, reduced inflammatory markers, and improved cognitive functioning in AD models in multiple studies. The effect of probiotic administration on Aβ remains ambiguous. B. longum (NK46), C. butyricum, and the mixture SLAB51 are the most promising probiotics, as positive improvements were found on almost all outcomes. The results of this animal review underline the potential of probiotic therapy as a treatment option in AD.