The relationship between gut microbiota and depressive disorder has become a research focus in recent years. Within the microbiota-gut-brain axis, the gut microbiota influences the onset and progression of depressive disorder primarily through the tryptophan metabolic pathway. Tryptophan, an essential amino acid in humans, is subject to dual regulation by intestinal microorganisms, which modulate its metabolic balance via inflammatory stimulation and microbial metabolite production. In depression, excessive activation of the kynurenine branch of tryptophan metabolism leads to the accumulation of proinflammatory and neurotoxic metabolites, thereby exacerbating neuroinflammation in the brain. Intervention studies indicate that the antidepressant-like effects of probiotics and traditional Chinese medicine are associated with remodeling of the gut microbiota, restoration of tryptophan metabolic balance, and alleviation of neuroinflammation. Furthermore, targeted inhibition of kynurenine 3-monooxygenase can mitigate neuroinflammation by regulating microglial activity, thus improving depressive-like behaviors. In summary, the metabolite-inflammation axis represents a central node in the interaction regulation between tryptophan metabolism and the microbiota-gut-brain axis. This provides a theoretical foundation for developing novel therapeutic strategies targeting depression through modulation of gut microbiota-mediated tryptophan metabolism.
Tryptophan/metabolism* ; Gastrointestinal Microbiome/physiology* ; Humans ; Depressive Disorder/microbiology* ; Probiotics/therapeutic use* ; Brain/metabolism* ; Kynurenine/metabolism* ; Metabolic Networks and Pathways ; Animals ; Medicine, Chinese Traditional

OBJECTIVES: To investigate the effects of early life intervention with Bifidobacterium bifidum BD-1 (B. bifidum BD-1) on hyperactivity in a female mouse model of attention deficit hyperactivity disorder (ADHD) and explore the underlying mechanisms. METHODS: Eight newborn female Wistar-Kyoto (WKY) rats and 6 spontaneous hypertensive rats (SHRs) were gavaged with saline and another 6 SHRs were gavaged with B. bifidum BD-1 (10⁹ CFU) daily for 3 weeks. Open field test of the rats was conducted at 7 weeks, and fecal samples were collected at weaning (3 weeks) and at 7 weeks for 16S rRNA sequencing. Immunofluorescent staining was used to detect dopamine transporter (DAT) and tyrosine hydroxylase (Th) levels in the striatum and activated microglia in the prefrontal cortex. Treg cells in the mesenteric lymph nodes, spleen and blood were analyzed using flow cytometry. RESULTS: The SHRs traveled a significantly greater distance in open fields test than WKY rats, and this behavior was significantly attenuated by B. bifidum BD-1 intervention. The expression of DAT and Th in the striatum was significantly lower in the SHRs than in WKY rats, while B. bifidum BD-1 treatment obviously increased Th levels in the SHRs. B. bifidum BD-1 intervention significantly deceased the number of activated microglia and increased Treg cell counts in the spleen of SHRs. The treatment also enhanced α diversity in gut microbiota of the SHRs and resulted in a decreased Firmicutes/Bacteroidota ratio, more active Muribaculaceae growth, and suppression of Clostridia_UCG-014 proliferation. CONCLUSIONS Early life intervention with B. bifidum BD-1 alleviates hyperactivity in female SHRs by modulating the gut microbiota and peripheral immune response, suppressing neuroinflammation and improving dopaminergic system function. These findings provide evidence for early prevention strategies and support the development and application of psychobiotics for ADHD.
Animals ; Female ; Rats ; Rats, Inbred WKY ; Rats, Inbred SHR ; Attention Deficit Disorder with Hyperactivity/therapy* ; Bifidobacterium bifidum ; Probiotics/therapeutic use* ; Dopamine Plasma Membrane Transport Proteins/metabolism* ; Tyrosine 3-Monooxygenase/metabolism* ; Gastrointestinal Microbiome ; Disease Models, Animal

OBJECTIVES: To investigate the efficacy of Lactobacillus plantarum ZG03 (L. plantarum ZG03) for ameliorating oxidative stress in zebrafish. METHODS: We evaluated the growth pattern of L. plantarum ZG03, observed its morphology using field emission scanning electron microscopy, and assessed its safety and potential efficacy with whole-genome sequencing for genetic analysis. FITC-labeled ZG03 was used to observe its intestinal colonization in zebrafish. In a zebrafish model of 2% glucose-induced oxidative stress, the effect of ZG03 was evaluated by assessing the changes in neutrophils in the caudal hematopoietic tissue (CHT), superoxide dismutase (SOD) activity, reactive oxygen species (ROS) levels, and malondialdehyde (MDA) content. Liquid chromatography-mass spectrometry-based targeted metabolomics was used for analyzing short-chain fatty acids (SCFAs) in the zebrafish, and the antioxidant effects of the key metabolites (acetate, propionate, and caproate) were tested. RESULTS: On MRS agar, L. plantarum ZG03 formed circular, smooth, moist, and milky-white colonies with a rod-shaped cell morphology. Genomic analysis revealed abundant sugar metabolism gene clusters. After inoculation of FITC-labeled L. plantarum ZG03 in zebrafish, green fluorescence was clearly observed in the intestinal bulb, mid-intestine, and hind intestine. In zebrafish with glucose-induced oxidative stress, L. plantarum ZG03 significantly reduced ROS levels and the number of neutrophils in the CHT with increased SOD activity. L.plantarum ZG03 significantly increased the content of SCFAs including acetic acid, propionic acid, and caproic acid in zebrafish metabolites. In addition, sodium acetate, sodium propionate, and sodium caproate in the SCFAs significantly increased SOD activity in the zebrafish models. CONCLUSIONS L. plantarum ZG03 ameliorates oxidative stress in a glucose-induced zebrafish model through its metabolites, particularly the SCFAs including acetic acid, propionic acid and caproic acid.
Animals ; Zebrafish/metabolism* ; Oxidative Stress ; Lactobacillus plantarum/metabolism* ; Fatty Acids, Volatile/metabolism* ; Probiotics ; Reactive Oxygen Species/metabolism* ; Superoxide Dismutase/metabolism*

We have isolated an intestinal probiotic strain, Pediococcus acidilactici HRQ-1. To improve its gastrointestinal fluid tolerance, transportation and storage stability, and slow-release properties, we employed the extrusion method to prepare the microcapsules with P. acidilactici HRQ-1 as the core material and sodium alginate and chitosan as the wall material. The optimal conditions for preparing the microcapsules were determined by single factor and orthogonal tests, and the optimal ratio was determined by taking the embedding rate, survival rate, storage stability, gastrointestinal fluid tolerance, and release rate as the evaluation indexes. The results showed that under the optimal embedding conditions, the embedding rate reached (89.60±0.02)%. Under the optimal formula of freeze-drying protective agent, the freeze-drying survival rate reached (76.42±0.13)%, and the average size of the microcapsules produced was (1.16±0.03) mm. The continuous gastrointestinal fluid simulation experiments confirmed that the microcapsules ensured the viable bacterial count and can slowly release bacteria in the intestinal fluid. The curve of the viable bacterial count during storage at 4 ℃ and room temperature indicated that the prepared microcapsules achieved strains' live number protection. The formula and preparation process of P. acidilactici microcapsules may provide a technological reserve for the preparation of more live bacterial drugs in the future.
Pediococcus acidilactici/chemistry* ; Probiotics/chemistry* ; Capsules/chemistry* ; Alginates/chemistry* ; Chitosan/chemistry* ; Drug Compounding/methods* ; Glucuronic Acid/chemistry* ; Hexuronic Acids/chemistry* ; Freeze Drying

Uric acid (UA) is the final metabolite of purines in the human body. An imbalance in UA production and excretion that disrupts homeostasis leads to elevated blood UA levels and the development of hyperuricemia (HUA). Approximately one-third of UA is excreted through the intestinal tract. As a crucial component of the intestinal microenvironment, the gut microbiota plays a pivotal role in regulating blood UA levels. Alterations or imbalances in gut microbiota composition are linked to the onset of HUA, which implies the potential of gut microbiota as a novel target for the prevention and treatment of HUA. This review introduces the occurrence mechanism and damage of hyperuricemia, examines the association between HUA and the gut microbiota and their metabolites, and explores the molecular mechanisms underlying gut microbiota-targeted therapies for HUA. Furthermore, it discusses the potential applications of probiotics, prebiotics, and traditional Chinese medicine (including both single herbs and compound formulas) with UA-lowering effects, along with cutting-edge technologies such as fecal microbiota transplantation and machine learning in HUA treatment. This review provides valuable perspectives and strategies for improving the prevention and treatment of HUA.
Hyperuricemia/microbiology* ; Humans ; Gastrointestinal Microbiome/physiology* ; Probiotics/therapeutic use* ; Uric Acid/blood* ; Fecal Microbiota Transplantation ; Prebiotics ; Medicine, Chinese Traditional

Diabetic chronic wounds are characterized by difficult healing, recurrent progression, and high rates of disability and mortality, which make their clinical treatment a medical challenge urgent to be addressed. However, the complex local microenvironment conditions of chronic wounds, such as high protease activity and persistent inflammatory responses, result in low bioavailability of exogenous cytokines (e.g., chemokine CXCL12) at the wound site, limiting their clinical application. In this study, we utilized Lactobacillus plantarum WCFS1 as the chassis to develop an efficient CXCL12 delivery system based on synthetic biology. Subsequently, we evaluated the role of the engineered probiotic strain in promoting the chronic wound healing in diabetic mice. Firstly, we fused the endogenous secretion signal peptide lp_3050 (SP_{lp_3050}) of L. plantarum WCFS1 and the commonly used secretion signal peptide usp45 (SP_usp45) of lactic acid bacteria with the reporter gene gusA and inserted them into the pTRK892-P_32(pgm) plasmid by molecular cloning. Then, we prepared the engineered strains and characterized the efficacy of the two signal peptides in driving the secretion of GusA. The results showed that SP_{lp_3050} efficiently drove the secretion of GusA in L. plantarum WCFS1, increasing the activity of GusA in the culture supernatant by nearly five times compared with that of SP_{lp_3050}. Further, we fused SP_{lp_3050} and codon-optimized CXCL12 gene to construct an engineered probiotic strain Lpw-CXCL12 for CXCL12 delivery. The results demonstrated that the content of CXCL12 in the culture supernatant reached (13.40±0.20) μg/mL. Finally, we found that the engineered probiotic strain Lpw-CXCL12 accelerated chronic wound healing in a diabetic mouse model. In conclusion, these results support an engineered probiotic strain in promoting diabetic chronic wound healing, providing a new strategy and technological foundation for the management of diabetic chronic wounds in the future.
Probiotics ; Animals ; Chemokine CXCL12/biosynthesis* ; Mice ; Wound Healing ; Lactobacillus plantarum/metabolism* ; Diabetes Mellitus, Experimental/complications* ; Male

Acute pancreatitis (AP) is a severe inflammatory disease characterized by self-digestion of pancreatic tissue and inflammatory responses. Recent studies have revealed a close connection between gut microbiota and AP. The gut microbiota community, a complex ecosystem composed of trillions of microorganisms, is closely associated with various physiological activities of the host, including metabolic processes, immune system regulation, and intestinal structure maintenance. However, in patients with AP, dysbiosis of the gut microbiota are believed to play a key role in the occurrence and progression of the disease. This dysbiosis not only impairs the integrity of the intestinal barrier, but may also exacerbate inflammatory responses through multiple mechanisms, thereby affecting the severity of the disease and patient' clinical prognosis. This article reviews the mechanisms of action of gut microbiota in AP, explores how gut microbiota dysbiosis affects disease progression, and evaluates current clinical treatment methods to regulate intestinal flora, including probiotic supplementation, fecal microbiota transplantation, antibiotic therapy, and early enteral nutrition. In addition, this article discusses the efficacy and safety of the aforementioned therapeutic approaches, and outlines future research directions, aiming to provide novel perspectives and strategies for the diagnosis, treatment and prognostic evaluation of AP. Through in-depth understanding the interaction between gut microbiota and AP, it is expected that more precise and personalized therapeutic regimens will be developed to improve patients' quality of life and clinical outcomes.
Humans ; Gastrointestinal Microbiome ; Dysbiosis ; Pancreatitis/microbiology* ; Fecal Microbiota Transplantation ; Probiotics/therapeutic use* ; Acute Disease ; Anti-Bacterial Agents/therapeutic use* ; Enteral Nutrition

OBJECTIVES: To investigate the protective effect of the probiotic bacterium Streptococcus salivarius K12 (K12) against Mycoplasma pneumoniae (Mp) infection in mice. METHODS: Forty male BALB/c mice were randomized into normal control group, K12 treatment group, Mp infection group, and K12 pretreatment prior to Mp infection group. The probiotic K12 was administered daily by gavage for 14 days before Mp infection induced by intranasal instillation of Mp. Three days after Mp infection, the mice were euthanized for analysis of bronchoalveolar lavage fluid (BALF) cell counts and serum levels of secretory immunoglobulin A (sIgA), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). RT-qPCR was performed to detect the P1 and community-acquired respiratory distress syndrome ( CARDS ) toxin of Mp in the lung tissues and the mRNA expressions of TNF-α, IL-6, chemokine 1 (CXCL1), matrix metalloproteinase 9 (MMP9), mucin 5ac (MUC5ac), collagen 3a1 (Col3a1), Toll-like receptor 2 (TLR2) and TLR4; the protein expressions of TLR2 and TLR4 in the lung tissue were detected using Western blotting. Pathological changes in the lung tissue and airway remodeling were examined with HE staining and AB/PAS staining. RESULTS: Compared with the Mp-infected mice with PBS treatment, the infected mice with K12 treatment showed significantly lowered mRNA levels of P1 and CARDS in the lung tissue and reduced white blood cell counts in the BALF (P<0.05). In spite of the absence of significant differences in serum levels of inflammatory factors between the two groups, the mRNA expressions of TNF‑α, IL-6, CXCL1, MMP9, MUC5ac and COL3A1 and the mRNA and protein levels of TLR2 and TLR4 in the lung tissues were significantly lower in K12-treated mice, in which AB/PAS staining showed obviously decreased mucus secretion. CONCLUSIONS K12 pretreatment can effectively reduce pulmonary inflammatory responses, improve airway remodeling and alleviate lung injury in Mp-infected mice.
Animals ; Mice ; Pneumonia, Mycoplasma/metabolism* ; Mice, Inbred BALB C ; Toll-Like Receptor 2/metabolism* ; Mycoplasma pneumoniae ; Male ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/metabolism* ; Lung/microbiology* ; Toll-Like Receptor 4/metabolism* ; Streptococcus salivarius ; Probiotics/administration & dosage* ; Bronchoalveolar Lavage Fluid ; Matrix Metalloproteinase 9/metabolism* ; Mucin 5AC/metabolism* ; Chemokine CXCL1/metabolism* ; Immunoglobulin A, Secretory/metabolism* ; Bacterial Toxins ; Bacterial Proteins

Humans ; Gastrointestinal Microbiome ; Constipation/therapy* ; Probiotics/therapeutic use* ; Patients

BACKGROUND

Long-term administration of conventional acne medications implies the potential risk of increasing microbial resistance, and safety risks. Recent interest has grown in probiotics as a potential treatment and as an adjunct for acne vulgaris.

To conduct a systematic review of randomized controlled trials of oral probiotics in reducing the severity of acne vulgaris compared to placebo or conventional treatments.

PubMed, Cochrane Central Register of Controlled Trials, Embase, WHO ICTRP and ClinicalTrials.gov were searched for relevant studies, and randomized controlled trials of acne vulgaris treatment with probiotic therapy were included. Outcomes include decrease in total lesion count/percent change from baseline, improvement of severity scores, inflammation related indicators, and gene expression. Changes in outcomes were calculated by effect size or pooled odds ratio.

A total of 2 RCTs involving 100 participants were included. Both studies show low risk on the risk bias criteria. The data of 2 RCTs reporting severity scores (AGSS and GAGS) supports that probiotics can improve their scores and thereby their condition. For inflammation-related indicators, only 1 RCT showed that probiotics can improve the IGF1 and FOXO1 gene expression in the skin. Regarding safety, only Eguren et al. reported adverse event. Their RCT showed that the incidence of adverse events was low and no serious adverse events.

In conclusion, the probiotics investigated in both studies may be given as adjuvant treatment for acne vulgaris as they improve the clinical course of patients.