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Chronic stress disrupts immune homeostasis while gut microbiota-derived metabolites attenuate inflammation, thus promoting resilience to stress-induced immune and behavioral abnormalities. There are both peripheral and brain region-specific maladaptations of the immune response to chronic stress that produce interrelated mechanistic considerations required for the design of novel therapeutic strategies for prevention of stress-induced psychological impairment. This study shows that a combination of probiotics and polyphenol-rich prebiotics, a synbiotic, attenuates the chronic-stress induced inflammatory responses in the ileum and the prefrontal cortex promoting resilience to the consequent depressive- and anxiety-like behaviors in male mice. Pharmacokinetic studies revealed that this effect may be attributed to specific synbiotic-produced metabolites including 4-hydroxyphenylpropionic, 4-hydroxyphenylacetic acid and caffeic acid. Using a model of chronic unpredictable stress, behavioral abnormalities were associated to strong immune cell activation and recruitment in the ileum while inflammasome pathways were implicated in the prefrontal cortex and hippocampus. Chronic stress also upregulated the ratio of activated proinflammatory T helper 17 (Th17) to regulatory T cells (Treg) in the liver and ileum and it was predicted with ingenuity pathway analysis that the aryl hydrocarbon receptor (AHR) could be driving the synbiotic's effect on the ileum's inflammatory response to stress. Synbiotic treatment indiscriminately attenuated the stress-induced immune and behavioral aberrations in both the ileum and the brain while in a gut-immune co-culture model, the synbiotic-specific metabolites promoted anti-inflammatory activity through the AHR. Overall, this study characterizes a novel synbiotic treatment for chronic-stress induced behavioral impairments while defining a putative mechanism of gut-microbiota host interaction for modulating the peripheral and brain immune systems.
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Microbioma Gastrointestinal , Microbiota , Animales , Ansiedad , Masculino , Ratones , Prebióticos , Linfocitos T ReguladoresRESUMEN
Cardiovascular diseases are the leading causes of mortality across the globe. Over the years, various drug formulations and delivery methods have been tested for cardiac repair. Milrinone (MRN) is a widely known cardiac inotrope drug used for the treatment of congestive heart failure in patients, however, its efficacy is limited. This study is the first to report the design of a novel MRN-nanoformulation using human serum albumin nanoparticles (HSA-NPs). The HSA-NPs exhibit promising drug delivery characteristics, such as target specificity, nonimmunogenicity, biocompatibility, and enhanced bioavailability. This article describes a MRN-nanoformulation design for in vitro drug release, cellular uptake, biocompatibility, and other features. The MRN-nanoformulation was prepared by the ethanol desolvation technique and key parameters were optimized to obtain a desired particle size of 154.2 ± 5.8 nm, zeta potential of -29.5 ± 2.9 mV, and a drug encapsulation efficiency of 41.1 ± 1.7%. Molecular docking studies have revealed that MRN binds in the hydrophobic cavity of HSA, which has also been indicated by circular dichroism and enzyme-mediated drug release studies in the presence of trypsin, pepsin, proteinase K, protease, and cathepsin D. The intracellular uptake of fluorescently tagged MRN-HSA-NPs using HUVEC and H9c2 cells was evaluated by flow cytometry. The nanoparticle toxicity results indicated that MRN-HSA-NPs show significantly lower cytotoxicity and higher cell viability ( P < 0.0001) as compared to the MRN-lactate drug in HUVEC (61.6 ± 3.7% vs 36.2 ± 2.9%) and H9c2 (58.8 ± 5.7% vs 18.8 ± 4.9%) cells. These studies indicate that the novel MRN-nanoformulation offers better drug delivery procedures than currently used methods and has potential in treatment of congestive heart failure and other cardiovascular diseases.
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Cardiotónicos/administración & dosificación , Enfermedades Cardiovasculares/tratamiento farmacológico , Portadores de Fármacos/química , Milrinona/administración & dosificación , Animales , Línea Celular , Dicroismo Circular , Composición de Medicamentos/métodos , Liberación de Fármacos , Células Endoteliales de la Vena Umbilical Humana , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Milrinona/química , Milrinona/farmacocinética , Simulación del Acoplamiento Molecular , Nanopartículas/química , Tamaño de la Partícula , Ratas , Albúmina Sérica Humana/químicaRESUMEN
The gut microbiota is essential to health and has recently become a target for live bacterial cell biotherapies for various chronic diseases including metabolic syndrome, diabetes, obesity and neurodegenerative disease. Probiotic biotherapies are known to create a healthy gut environment by balancing bacterial populations and promoting their favorable metabolic action. The microbiota and its respective metabolites communicate to the host through a series of biochemical and functional links thereby affecting host homeostasis and health. In particular, the gastrointestinal tract communicates with the central nervous system through the gut-brain axis to support neuronal development and maintenance while gut dysbiosis manifests in neurological disease. There are three basic mechanisms that mediate the communication between the gut and the brain: direct neuronal communication, endocrine signaling mediators and the immune system. Together, these systems create a highly integrated molecular communication network that link systemic imbalances with the development of neurodegeneration including insulin regulation, fat metabolism, oxidative markers and immune signaling. Age is a common factor in the development of neurodegenerative disease and probiotics prevent many harmful effects of aging such as decreased neurotransmitter levels, chronic inflammation, oxidative stress and apoptosis-all factors that are proven aggravators of neurodegenerative disease. Indeed patients with Parkinson's and Alzheimer's diseases have a high rate of gastrointestinal comorbidities and it has be proposed by some the management of the gut microbiota may prevent or alleviate the symptoms of these chronic diseases.
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Microbioma Gastrointestinal , Enfermedades Neurodegenerativas/microbiología , Enfermedades Neurodegenerativas/terapia , Probióticos/uso terapéutico , Animales , Encéfalo/metabolismo , Encéfalo/patología , Ácidos Cumáricos/metabolismo , Disbiosis/complicaciones , Ácidos Grasos/metabolismo , Ghrelina/metabolismo , Histamina/metabolismo , Humanos , Quinurenina/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Enfermedades Neurodegenerativas/patología , Estrés Oxidativo , Transducción de SeñalRESUMEN
Probiotics have been shown to have beneficial properties in attenuating the risk of colorectal cancer (CRC) development. However, functional evidence to support such effects for some probiotic bacteria are relatively unknown. Here, we document a significant antioxidant, anti-proliferative and pro-apoptotic activities of Lactobacillus acidophilus ATCC 314 and Lactobacillus fermentum NCIMB 5221 on CRC cells, particularly when used in combination (La-Lf). Furthermore, a superior synergistic activity on the inhibition of tumor growth and modulation of cell proliferation and epithelial markers in the Apc Min/+ CRC mouse model was explored, based on the expression levels of Ki-67, E-cadherin, ß-catenin, and cleaved caspase-3 (CC3) proteins. The anti-cancer activity of La-Lf co-culture was significantly enhanced in vitro with significant reduced proliferation (38.8 ± 6.9 %, P = 0.009) and increased apoptosis (413 RUL, P < 0.001) towards cancer cells, as well as significant protection of normal colon cell growth from toxic treatment (18.6 ± 9.8 %, P = 0.001). La-Lf formulation (1010cfu/animal/day) altered aspects of intestinal tumorigenesis by significantly reducing intestinal tumor multiplicity (1.7-fold, P = 0.016) and downregulating cellular proliferation markers, including ß-catenin (P = 0.041) and Ki-67 (P = 0.008). In conclusion, La-Lf showed greater protection against intestinal tumorigenesis supporting a potential use as a biotherapeutic for the prevention of CRC.
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Antioxidantes/uso terapéutico , Carcinogénesis/efectos de los fármacos , Extractos Celulares/uso terapéutico , Neoplasias Colorrectales/prevención & control , Lactobacillus acidophilus/metabolismo , Limosilactobacillus fermentum/metabolismo , Probióticos/uso terapéutico , Animales , Apoptosis/efectos de los fármacos , Células CACO-2 , Cadherinas/biosíntesis , Caspasa 3/biosíntesis , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Neoplasias Colorrectales/terapia , Modelos Animales de Enfermedad , Humanos , Antígeno Ki-67/biosíntesis , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , beta Catenina/biosíntesisRESUMEN
Maneb (MB) and paraquat (PQ) are environmental toxins that have been experimentally used to induce selective damage of dopaminergic neurons leading to the development of Parkinson's disease (PD). Although the mechanism of this selective neuronal toxicity in not fully understood, oxidative stress has been linked to the pathogenesis of PD. The present study investigates the mechanisms of neuroprotection elicited by Withania somnifera (Ws), a herb traditionally recognized by the Indian system of medicine, Ayurveda. An ethanolic root extract of Ws was co-treated with the MB-PQ induced mouse model of PD and was shown to significantly rescue canonical indicators of PD including compromised locomotor activity, reduced dopamine in the substantia nigra and various aspects of oxidative damage. In particular, Ws reduced the expression of iNOS, a measure of oxidative stress. Ws also significantly improved the MB + PQ mediated induction of a pro-apoptotic state by reducing Bax and inducing Bcl-2 protein expression, respectively. Finally, Ws reduced expression of the pro-inflammatory marker of astrocyte activation, GFAP. Altogether, the present study suggests that Ws treatment provides nigrostriatal dopaminergic neuroprotection against MB-PQ induced Parkinsonism by the modulation of oxidative stress and apoptotic machinery possibly accounting for the behavioural effects.
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Apoptosis/efectos de los fármacos , Dopamina/metabolismo , Neuronas/efectos de los fármacos , Enfermedad de Parkinson/prevención & control , Extractos Vegetales/farmacología , Withania/química , Secuencia de Bases , Western Blotting , Cromatografía Líquida de Alta Presión , Cartilla de ADN , Humanos , Neuronas/metabolismo , Reacción en Cadena de la PolimerasaRESUMEN
Scope: The goal of this study is to investigate the effects of a bioactive dietary polyphenol preparation (BDPP), which is made up of grape-derived polyphenols, on microglial responses, as well as the underlying molecular mechanisms in depression and anxiety-like behaviors. Methods and results: We find that treatment with BDPP significantly decreased depression-like and anxiety-like behaviors induced by chronic stress in mice, while leaving their locomotor activity unaffected. We also find that BDPP treatment reversed microglia activation in the amygdala and hippocampal formation, regions of the brain involved in emotional regulation, from an amoeboid shape to ramified shape. Additionally, BDPP treatment modulates the release of pro-inflammatory cytokines such as interleukin-6 via high mobility box 1 protein and the receptor for advanced glycation end products (HMGB1-RAGE) signaling pathway in activated microglia induced by chronic stress. Conclusion: Our findings suggest regional heterogeneity in microglial responses following chronic stress in subregions of the corticolimbic circuit. Specifically, activation of the immune-inflammatory HMGB1-RAGE pathway might provide a new avenue for therapeutic intervention in stress-induced anxiety- and depression-like behavior, using bioactive and bioavailable polyphenols.
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Enteric helminths form intimate physical connections with the intestinal epithelium, yet their ability to directly alter epithelial stem cell fate has not been resolved. Here we demonstrate that infection of mice with the parasite Heligmosomoides polygyrus bakeri (Hpb) reprograms the intestinal epithelium into a fetal-like state marked by the emergence of Clusterin-expressing revival stem cells (revSCs). Organoid-based studies using parasite-derived excretory-secretory products reveal that Hpb-mediated revSC generation occurs independently of host-derived immune signals and inhibits type 2 cytokine-driven differentiation of secretory epithelial lineages that promote their expulsion. Reciprocally, type 2 cytokine signals limit revSC differentiation and, consequently, Hpb fitness, indicating that helminths compete with their host for control of the intestinal stem cell compartment to promote continuation of their life cycle.
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Nematospiroides dubius , Infecciones por Strongylida , Animales , Citocinas , Mucosa Intestinal , Intestinos , Ratones , Células MadreRESUMEN
Congestive heart failure, a prominent cardiovascular disease results primarily from myocardial infarction or ischemia. Milrinone (MRN), a widely used clinical drug for heart failure, improves myocardial contractility and cardiac function through its inotropic and vasodilatory effects. However, lacking target specificity, it exhibits low bioavailability and lower body retention time. Therefore, in this study, angiotensin II (AT1) peptide conjugated human serum albumin nanoparticles (AT1-HSA-MRN-NPs) have been synthesized for targeted delivery of MRN to the myocardium, overexpressing AT1 receptors under heart failure. The NPs were surface functionalized through a covalent conjugation reaction between HSA and AT1. Nanoparticle size was 215.2±4.7 nm and zeta potential -28.8±2.7 mV and cumulative release of MRN was ~72% over 24 hrs. The intracellular uptake of nanoparticles and cell viability was studied in H9c2 cells treated with AT1-MRN-HSA-NPs vs the control non-targeted drug, MRN Lactate under normal, hypoxic and hypertrophic conditions. The uptake of AT1-HSA-MRN-NPs in H9c2 cells was significantly higher as compared to non-targeted nanoparticles, and the viability of H9c2 cells treated with AT1-MRN-HSA-NPs vs MRN Lactate was 73.4±1.4% vs 44.9±1.4%, respectively. Therefore, AT1-HSA-MRN-NPs are safe for in vivo use and exhibit superior targeting and drug delivery characteristics for treatment of heart failure.
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Sistemas de Liberación de Medicamentos , Milrinona/farmacología , Miocitos Cardíacos/efectos de los fármacos , Nanopartículas/administración & dosificación , Fragmentos de Péptidos/farmacología , Albúmina Sérica Humana/química , Animales , Transporte Biológico , Cardiotónicos/química , Cardiotónicos/farmacología , Supervivencia Celular , Portadores de Fármacos , Humanos , Milrinona/química , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Nanopartículas/química , Fragmentos de Péptidos/química , RatasRESUMEN
Chronic stress manifests as depressive- and anxiety-like behavior while recurrent stress elicits disproportionate behavioral impairments linked to stress-induced immunological priming. The gut-brain-microbiota-axis is a promising therapeutic target for stress-induced behavioral impairments as it simultaneously modulates peripheral and brain immunological landscapes. In this study, a combination of probiotics and prebiotics, known as a synbiotic, promoted behavioral resilience to chronic and recurrent stress by normalizing gut microbiota populations and promoting regulatory T cell (Treg) expansion through modulation of ileal innate lymphoid cell (ILC)3 activity, an impact reflecting behavioral responses better than limbic brain region neuroinflammation. Supporting this conclusion, a multivariate machine learning model correlatively predicted a cross-tissue immunological signature of stress-induced behavioral impairment where the ileal Treg/T helper17 cell ratio associated to hippocampal chemotactic chemokine and prefrontal cortex IL-1ß production in the context of stress-induced behavioral deficits. In conclusion, stress-induced behavioral impairments depend on the gut-brain-microbiota-axis and through ileal immune regulation, synbiotics attenuate the associated depressive- and anxiety-like behavior.
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Microbioma Gastrointestinal/fisiología , Neuroinmunomodulación/inmunología , Estrés Psicológico/inmunología , Simbióticos , Animales , Ansiedad/etiología , Ansiedad/inmunología , Depresión/etiología , Depresión/inmunología , Masculino , Ratones Endogámicos C57BL , Estrés Psicológico/complicacionesRESUMEN
Congestive heart failure is a fatal cardiovascular disease resulting in tissue necrosis and loss of cardiac contractile function. Inotropic drugs such as milrinone are commonly used to improve the myocardial contractility and heart function. However, milrinone is associated with severe side effects and lower circulation time. In this article, a novel protein nanoparticle formulation for heart-targeted delivery of milrinone has been designed and tested. The formulation was prepared using albumin protein conjugated with the targeting ligand, angiotensin II peptide to form nanoparticles following the ethanol desolvation method. The formulation was characterized for size, charge, and morphology and tested in a rat model of congestive heart failure to study pharmacokinetics, biodistribution, and efficacy. The overall cardiac output parameters were evaluated comparing the formulation with the control non-targeted drug, milrinone lactate. This formulation exhibited improved pharmacokinetics with a mean retention time of 123.7 min, half-life of 101.3 min, and clearance rate of 0.24 L/(kg*h). The targeted formulation also significantly improved ejection fraction and fractional shortening parameters thus improving cardiac function. This study demonstrates a new approach in delivering inotropic drugs such as milrinone for superior treatment of congestive heart failure.
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The gut microbiota's metabolome is composed of bioactive metabolites that confer disease resilience. Probiotics' therapeutic potential hinges on their metabolome altering ability; however, characterizing probiotics' metabolic activity remains a formidable task. In order to solve this problem, an artificial model of the human gastrointestinal tract is introduced coined the ABIOME (A Bioreactor Imitation of the Microbiota Environment) and used to predict probiotic formulations' metabolic activity and hence therapeutic potential with machine learning tools. The ABIOME is a modular yet dynamic system with real-time monitoring of gastrointestinal conditions that support complex cultures representative of the human microbiota and its metabolome. The fecal-inoculated ABIOME was supplemented with a polyphenol-rich prebiotic and combinations of novel probiotics that altered the output of bioactive metabolites previously shown to invoke anti-inflammatory effects. To dissect the synergistic interactions between exogenous probiotics and the autochthonous microbiota a multivariate adaptive regression splines (MARS) model was implemented towards the development of optimized probiotic combinations with therapeutic benefits. Using this algorithm, several probiotic combinations were identified that stimulated synergistic production of bioavailable metabolites, each with a different therapeutic capacity. Based on these results, the ABIOME in combination with the MARS algorithm could be used to create probiotic formulations with specific therapeutic applications based on their signature metabolic activity.
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Tracto Gastrointestinal/fisiología , Aprendizaje Automático , Probióticos/uso terapéutico , Algoritmos , Microbioma Gastrointestinal , Tracto Gastrointestinal/metabolismo , Tracto Gastrointestinal/microbiología , HumanosRESUMEN
BACKGROUND: Dysbiotic microbiota in the gastrointestinal tract promotes and aggravates neurodegenerative disorders. Alzheimer's disease (AD) has been shown to correlate to dysbiotic bacteria and the immune, metabolic, and endocrine abnormalities associated with abnormal gut-brain-axis signaling. Recent reports also indicate that brain dysbacteriosis may play a role in AD pathogenesis. OBJECTIVE: To evaluate the presence and differences of brain-region dependent microbiomes in control and AD subjects and the contribution of study bias. METHODS: Two independent cohorts of postmortem AD brain samples were collected from separate locations, processed with different extraction protocols and investigated for the presence of bacterial DNA indicative of a brain microbiome with V4 16S next generation sequencing. RESULTS: In both cohorts, few differences between the control and AD groups were observed in terms of alpha and beta diversities, phyla and genera proportions. Independent of study in both AD and control subjects the most abundant phyla were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Variations in beta diversity between hippocampal and cerebellum samples were observed indicating an impact of brain region on the presence of microbial DNA. Importantly, differences in alpha and beta diversities between the two independent cohorts were found indicating a significant cohort- and processing-dependent effect on the microbiome. Finally, there were cohort-specific correlations between the gut microbiome and subject demographics indicate that postmortem interval may have a significant impact on brain microbiome determination. CONCLUSIONS: Regardless of the study bias, this study concludes that bacterial DNA can be isolated from the human brain suggesting that a brain microbiome may exist; however, more studies are required to understand the variation in AD.
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Enfermedad de Alzheimer/microbiología , Encéfalo/microbiología , Microbiota , Degeneración Nerviosa/microbiología , Disbiosis/microbiología , Femenino , Humanos , MasculinoRESUMEN
The pathophysiology of depression is multifactorial yet generally aggravated by stress and its associated physiological consequences. To effectively treat these diverse risk factors, a broad acting strategy is required and is has been suggested that gut-brain-axis signaling may play a pinnacle role in promoting resilience to several of these stress-induced changes including pathogenic load, inflammation, HPA-axis activation, oxidative stress and neurotransmitter imbalances. The gut microbiota also manages the bioaccessibility of phenolic metabolites from dietary polyphenols whose multiple beneficial properties have known therapeutic efficacy against depression. Although several potential therapeutic mechanisms of dietary polyphenols toward establishing cognitive resilience to neuropsychiatric disorders have been established, only a handful of studies have systematically identified how the interaction of the gut microbiota with dietary polyphenols can synergistically alleviate the biological signatures of depression. The current review investigates several of these potential mechanisms and how synbiotics, that combine probiotics with dietary polyphenols, may provide a novel therapeutic strategy for depression. In particular, synbiotics have the potential to alleviate neuroinflammation by modulating microglial and inflammasome activation, reduce oxidative stress and balance serotonin metabolism therefore simultaneously targeting several of the major pathological risk factors of depression. Overall, synbiotics may act as a novel therapeutic paradigm for neuropsychiatric disorders and further understanding the fundamental mechanisms of gut-brain-axis signaling will allow full utilization of the gut microbiota's as a therapeutic tool.
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The gut-brain-axis (GBA) describing the bidirectional communication between the gut microbiota and brain was recently implicated in Alzheimer's disease (AD). The current study describes a novel synbiotic containing three metabolically active probiotics and a novel polyphenol-rich prebiotic which has beneficial impacts on the onset and progression of AD. In a transgenic humanized Drosophila melanogaster model of AD, the synbiotic increased survivability and motility and rescued amyloid beta deposition and acetylcholinesterase activity. Such drastic effects were due to the synbiotic's combinatorial action on GBA signaling pathways including metabolic stability, immune signaling, oxidative and mitochondrial stress possibly through pathways implicating PPARγ. Overall, this study shows that the therapeutic potential of GBA signaling is best harnessed in a synbiotic that simultaneously targets multiple risk factors of AD.
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Enfermedad de Alzheimer , Péptidos beta-Amiloides , Encéfalo , Tracto Gastrointestinal , Transducción de Señal , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/microbiología , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/genética , Péptidos beta-Amiloides/metabolismo , Animales , Animales Modificados Genéticamente , Encéfalo/metabolismo , Encéfalo/patología , Modelos Animales de Enfermedad , Drosophila melanogaster , Tracto Gastrointestinal/metabolismo , Tracto Gastrointestinal/microbiología , Tracto Gastrointestinal/patología , Humanos , Prebióticos , Probióticos/farmacologíaRESUMEN
The composition and activity of the gut microbiota impacts several energy-regulating conditions including diabetes, obesity and metabolic syndrome; however, the specific mechanisms linking the gut microbiota with the host's energy homeostasis remain elusive. Probiotics are health-promoting bacteria that when consumed, alter the composition and/or metabolism of resident microbiota conferring health benefits. To assess the role of a specific probiotic treatment on microbiota-derived impacts on energy homeostasis in the context of development, Drosophila melanogaster larvae were orally administered the probiotic Lactobacillus fermentum NCIMB 5221 or its metabolic product, ferulic acid: a potent anti-inflammatory and anti-oxidant hydroxycinnamic acid. In Drosophila larvae, both the probiotic and metabolite treatments advanced the nutritionally dependent stages of development in a dose-dependent manner while not affecting the hormonally controlled pupariation stage. These treatments correspondingly accelerated the developmental phase-dependent 20-hydroxyecdysone and insulin receptor gene expression surges and altered the phasic expression of downstream insulin signalling factors including dAkt, dTOR and dFOXO indicating a deep level of nutritionally dependent regulatory control. Administering Drosophila both ferulic acid and the TOR inhibitor rapamycin eliminated the physiological and molecular developmental advances indicating that microbial ferulic acid affects energy utilization in a dTOR-dependent manner outlining a potential mechanism of action of L. fermentum NCIMB 5221 on modulating microbiota dynamics to modulate energy homeostasis. TOR conservation from flies to humans indicates that probiotic therapy with L. fermentum NCIMB 5221 has a high therapeutic potential towards several human energy regulatory diseases such as obesity, diabetes and cancer.
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Ácidos Cumáricos/metabolismo , Ácidos Cumáricos/farmacología , Proteínas de Drosophila/metabolismo , Larva , Limosilactobacillus fermentum/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Animales , Drosophila melanogaster/efectos de los fármacos , Drosophila melanogaster/crecimiento & desarrollo , Femenino , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , Masculino , Transducción de Señal/efectos de los fármacosRESUMEN
The amyloid hypothesis of Alzheimer's disease (AD) has become outdated as researchers and clinicians recognize that lifestyle factors and environmental stressors have a greater impact on the etiology of AD than genetic predispositions. When persistent over decades, chronic psychological and physical stressors disrupt the body's natural adaptions to stress (allostasis) resulting in a general "wear and tear" on the body termed allostatic overload. Allostatic overload results in hypercortisolemia, disrupted hypothalamic-pituitary-adrenal (HPA) axis regulation, elevated proinflammatory cytokines and chemokines, reduced synaptic plasticity, persistently activated microglia, and importantly, a dysbiotic gut microbiota. This plethora of physiological maladaptations precedes the canonical symptoms of AD, including amyloid-beta plaque accumulation and tau hyperphosphorylation, indicating that a successful therapeutic approach to AD must first alleviate these risk factors. In this chapter, the use of gut microbiota modifying synbiotics, a combination of probiotics and prebiotics, to simultaneously and sustainably alleviate stress-induced AD risk factors is proposed. Synbiotic-derived bioactive metabolites can increase the integrity of the gut epithelial barrier preventing the infiltration of bacterial peptides and other immune-activating substances. These metabolites can also alter the balance of peripheral immune cells toward an anti-inflammatory state, protecting the body against stress-induced inflammatory challenges. These peripheral adaptations ultimately promote cognitive resilience to stress-induced AD by preventing microglia inflammasome activation, reinstating HPA axis negative feedback loops and allowing healthy neurogenic and neuroplasticity processes to ensue. Overall, synbiotics provide a novel treatment paradigm for AD that promote a sustainable allostasis to chronic stress, protecting the brain from the neuropathologies driving AD.
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Alostasis , Enfermedad de Alzheimer/prevención & control , Microbioma Gastrointestinal , Inflamación/complicaciones , Enfermedades del Sistema Nervioso/complicaciones , Estrés Fisiológico , Enfermedad de Alzheimer/etiología , Enfermedad de Alzheimer/patología , Animales , Humanos , Factores de RiesgoRESUMEN
The intestinal microbiota actively converts dietary flavanols into phenolic acids, some of which are bioavailable in vivo and may promote resilience to select neurological disorders by interfering with key pathologic mechanisms. Since every person harbors a unique set of gut bacteria, we investigated the influence of the gut microbiota's interpersonal heterogeneity on the production and bioavailability of flavonoid metabolites that may interfere with the misfolding of alpha (α)-synuclein, a process that plays a central role in Parkinson's disease and other α-synucleinopathies. We generated two experimental groups of humanized gnotobiotic mice with compositionally diverse gut bacteria and orally treated the mice with a flavanol-rich preparation (FRP). The two gnotobiotic mouse groups exhibited distinct differences in the generation and bioavailability of FRP-derived microbial phenolic acid metabolites that have bioactivity towards interfering with α-synuclein misfolding or inflammation. We also demonstrated that these bioactive phenolic acids are effective in modulating the development and progression of motor dysfunction in a Drosophila model of α-synucleinopathy. Lastly, through in vitro bacterial fermentation studies, we identified select bacteria that are capable of supporting the generation of these bioavailable and bioactive phenolic acids. Outcomes from our studies provide a better understanding of how interpersonal heterogeneity in the gut microbiota differentially modulates the efficacy of dietary flavanols to protect against select pathologic mechanisms. Collectively, our findings provide the basis for future developments of probiotic, prebiotic, or synbiotic approaches for modulating the onset and/or progression of α-synucleinopathies and other neurological disorders involving protein misfolding and/or inflammation.
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Microbioma Gastrointestinal/fisiología , Polifenoles/farmacocinética , Sinucleinopatías/metabolismo , alfa-Sinucleína/metabolismo , alfa-Sinucleína/toxicidad , Animales , Animales Modificados Genéticamente , Disponibilidad Biológica , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/patología , Modelos Animales de Enfermedad , Drosophila , Femenino , Humanos , Masculino , Ratones Endogámicos C57BL , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/patología , Polifenoles/metabolismo , Agregación Patológica de Proteínas/metabolismo , Pliegue de Proteína , Organismos Libres de Patógenos Específicos , Sinucleinopatías/patología , alfa-Sinucleína/química , alfa-Sinucleína/genéticaRESUMEN
The increasing prevalence of the metabolic syndrome has made it a medical issue that currently affects 1 in 5 Canadians. The metabolic syndrome is defined by risk factors that predispose an individual to diabetes and cardiovascular disease. Current forms of interventions have been inadequate as substantiated by the fact that the prevalence of metabolic syndrome has not reduced over the years. The objective of this study was to investigate the therapeutic benefits of a novel microencapsulated probiotic blend in treating the metabolic syndrome. Three probiotic strains were microencapsulated into alginate-polylysine-alginate (APA) microcapsules: L. rhamnosus NCIMB 6375, L. plantarum NCIMB 8826 and L. fermentum NCIMB 5221. From the results, it was observed that the microencapsulated probiotic blend significantly reduced serum total cholesterol, LDL cholesterol and triglyceride levels (reducing from 516 mg/dL to 379 mg/dL, 314 mg/dL to 231 mg/dL and 580 mg/dL to 270 mg/dL, respectively). In addition, the administration of the microencapsulated probiotic blend was found to favourably influence the gut microbiota, decreasing Firmicutes levels and increasing Bacteroidetes levels. Overall, this work demonstrates the potential a microencapsulated probiotic blend could have in targeting multiple risk factors of the metabolic syndrome; however, greater research is still needed.
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Composición de Medicamentos , Microbioma Gastrointestinal/efectos de los fármacos , Lactobacillus , Síndrome Metabólico/tratamiento farmacológico , Probióticos , Animales , Cápsulas , Lípidos/sangre , Mesocricetus , Síndrome Metabólico/sangre , Síndrome Metabólico/microbiología , Síndrome Metabólico/patología , Probióticos/química , Probióticos/farmacologíaRESUMEN
The gut microbiota is a vast community of synergistic bacterial species providing health benefits to the host. Imbalances in the gut microbiota (dysbiosis) due to diet, antibiotic use, age and stress contribute to disease development including diabetes, obesity, colon cancer, inflammatory bowel disease, inflammaging and neurodegeneration. Fortunately, a probiotic regime with a diet rich in prebiotics may reverse dysbiosis promoting health and wellness in age. The current study designs, optimizes and tests a novel probiotic and synbiotic formulation consisting of three metabolically active probiotics Lactobacillus plantarum, Lactobacillus fermentum and Bifidobacteria infantis together with a novel polyphenol-rich prebiotic, Triphala. The prebiotic action of Triphala was characterized using in vitro batch cultures, Drosophila melanogaster and a simulated model of the human gastrointestinal tract (SHIME) where in each model, Triphala supported growth of beneficial bacteria while inhibiting pathogenic species. Neither Triphala at 0.5% w/v nor the individual probiotics at 5.0 × 108 to 7.5 × 109 CFU/ml demonstrated toxicity in Drosophila. Interestingly, motility was combinatorially enhanced by the probiotic and synbiotic formulations reflecting the beneficial variations in the gut microbiota. Altogether, the present study shows that probiotics and synbiotics in combination are more effective at modulating the gut microbiota and eliciting biological effects than their components.