Trust the gut: outcomes of gut microbiota transplant in metabolic and cognitive disorders

Amomum tsao-ko Attenuates Hyperglycemia and Cognitive Impairment via Regulating Gut Microbiota, SCFAs, and CREB/BDNF/TrkB Signaling Pathway in T2DM Mice

BACKGROUND

As a medicine-food fruit, Amomum tsao-ko has been reported to be beneficial for the management of diabetes. However, its effects and mechanisms in the cognitive impairment caused by diabetes remain unclear. This study aimed to investigate the influences of A. tsao-ko on cognitive impairment in type 2 diabetes mellitus (T2DM) mice and associated mechanisms.

METHODS

A. tsao-ko was characterized using UHPLC-Q-Orbitrap-MS/MS. T2DM mice induced by a high-fat diet combined with streptozotocin were treated with ethanol extract of A. tsao-ko (EEAT) for 8 weeks. The cognitive function was evaluated by the Morris water maze (MWM) test, open field test (OFT), and novel object recognition test (NORT). Hippocampus and colon tissues were used for histopathology, biochemical assays, or protein expression analysis. Additionally, fecal samples were subjected to 16S rRNA gene sequencing and short-chain fatty acids (SCFAs) detection.

KEY RESULTS

The findings demonstrated that EEAT significantly reversed glucose metabolism disorders and cognitive deficits in T2DM mice. It promoted the protein expression of the CREB/BDNF/TrkB pathway and reduced hippocampal inflammatory responses, thereby improving neuronal damage. It inhibited the loss of colonic tight junction proteins, decreased the levels of inflammatory factors in the colon, and also reshaped the gut microbiota and increased SCFAs. Notably, Spearman's correlation analysis indicated that the Lachnospiraceae NK4A136 group, Ruminococcaceae UCG-014, Lactobacillus, Blautia, and Lachnoclostridium were obviously correlated (positive or negative) with glucose homeostasis indexes, behavioral indexes, tissue inflammatory factors, and SCFAs.

CONCLUSIONS

The regulating effects of Amomum tsao-ko on gut microbiota, SCFAs, and the CREB/BDNF/TrkB pathway may be potential mechanisms for alleviating cognitive impairment in diabetes, which provides a potential option to treat diabetic cognitive impairment.

Effects of children's microbiota on adipose and intestinal development in sex-matched mice persist into adulthood following a single fecal microbiota transplantation

BACKGROUND

The global prevalence of obesity and type 2 diabetes, particularly among children, is rising, yet the long-term impacts of early-life fecal microbiota transplantation (FMT) on metabolic health remain poorly understood.

OBJECTIVES

To investigate how early-life FMT from children to young, sex-matched mice influences metabolic outcomes and adipose tissue function in later, adult life.

METHODS

Germ-free mice were colonized with fecal microbiota from either lean children or children with obesity. The impacts on brown adipose tissue (BAT), white adipose tissue (WAT), glucose metabolism, and gut health were analyzed in male and female mice. Microbial communities and metabolite profiles were characterized using sequencing and metabolomics.

RESULTS

Male mice receiving FMT from obese donors exhibited marked BAT whitening and impaired amino acid and glucose metabolism. In contrast, female recipients developed hyperglycemia, accompanied by gut barrier dysfunction and WAT impairment. Distinct microbial and metabolite profiles were associated with these phenotypes: Collinsella and trimethylamine in females; and Paraprevotella, Collinsella, Lachnospiraceae NK4A136, Bacteroides, Coprobacillus, and multiple metabolites in males. These phenotypic effects persisted despite changes in host environment and diet.

CONCLUSIONS

Early-life FMT induced long-lasting effects on the metabolic landscape, profoundly affecting adipose tissue function and systemic glucose homeostasis in adulthood. Donor dietary habits correlated with the fecal microbial profiles observed in recipient mice. These findings highlight the critical need for identifying and leveraging beneficial exposures during early development to combat obesity and diabetes.

The Mechanism and Treatment of Cognitive Dysfunction in Diabetes: A Review

Diabetes mellitus (DM) is one of the fastest growing diseases in terms of global incidence and seriously affects cognitive function. The incidence rate of cognitive dysfunction is up to 13% in diabetes patients aged 65-74 years and reaches 24% in those aged >75 years. The mechanisms and treatments of cognitive dysfunction associated with diabetes mellitus are complicated and varied. Previous studies suggest that hyperglycemia mainly contributes to cognitive dysfunction through mechanisms involving inflammation, autophagy, the microbial-gut-brain axis, brain-derived neurotrophic factors, and insulin resistance. Antidiabetic drugs such as metformin, liraglutide, and empagliflozin and other drugs such as fingolimod and melatonin can alleviate diabetes-induced cognitive dysfunction. Self-management, intermittent fasting, and repetitive transverse magnetic stimulation can also ameliorate cognitive impairment. In this review, we discuss the mechanisms linking diabetes mellitus with cognitive dysfunction and propose a potential treatment for cognitive decline associated with diabetes mellitus.

Neuroglia and the microbiota-gut-brain axis

Glial cells are key players in the regulation of nervous system functioning in both the central and enteric nervous systems. Glial cells are dynamic and respond to environmental cues to modulate their activity. Increasing evidence suggests that these signals include those originating from the gut microbiota, the community of microorganisms, including bacteria, viruses, archaea, and protozoa, that inhabit the gut. The gut microbiota and the brain communicate in a bidirectional manner across multiple signaling pathways and interfaces that together comprise the microbiota-gut-brain axis. Here, we detail the role of glial cells, including astrocytes, microglia, and oligodendrocytes in the central nervous system, and glial cells in the enteric nervous system along this gut-brain axis. We review what is known regarding the modulation of glia by microbial signals, in particular by microbial metabolites which signal to the brain through systemic circulation and via the vagus nerve. In addition, we highlight what is yet to be discovered regarding the role of other gut microbiota signaling pathways in glial cell modulation and the challenges of research in this area.

Therapeutic Potential of Fecal Microbiota Transplantation in Type 2 Diabetes Mellitus: A Systematic Review

Diabetes mellitus is a chronic metabolic disease characterized by insulin resistance and hyperglycemia. It can cause various complications, which result in significant morbidity and mortality. There are multiple treatment options available to combat this disease; however, despite this, the incidence of type 2 diabetes mellitus is continuously increasing. Some promising results have shown that dysbiosis has a role in the pathogenesis of type 2 diabetes mellitus and fecal microbiota transplantation (FMT) in animals; however, the usage of FMT in humans needs further clarification and review. We explored PubMed, Popline, and Cochrane Library to identify relevant papers. Eight articles were then finalized after screening and applying eligibility criteria. These articles explored the role of the therapeutic efficacy of FMT in insulin resistance and hyperglycemia. The studies showed that the FMT had a positive impact on managing hyperglycemia and insulin resistance, which is evident in the decline of blood glucose and HBA1c levels and the rise of insulin and C-peptides. In addition, FMT also helped to control other risk factors such as hyperlipidemia and blood pressure; however, the impact on weight loss is not convincing. FMT also influenced the levels of some microbiota, which could be involved in controlling hyperglycemia and insulin resistance. Due to limited control trials and study periods and the small sample size of diabetic patients, more research is needed to explore the impact of FMT in controlling type 2 diabetes mellitus.

Dementia and metabolic syndrome: a bibliometric analysis

Background

Dementia is a progressive neurodegenerative condition, while metabolic syndrome (MetS) is characterized by a combination of metabolic abnormalities such as hypertension, high blood sugar, and obesity. There exists a connection and overlap between the two conditions in certain aspects, and both are influenced to varying degrees by the process of aging. This study presents an overview of the current research landscape regarding dementia and MetS through bibliometric analysis.

Methods

A systematic search was conducted to retrieve relevant literature on dementia and MetS published between 1 January 2000, and 30 November 2023, from the Web of Science Core Collection database. Various bibliometric tools, including VOSviewer, CiteSpace, and the R software package "bibliometrix," were utilized for analysis.

Results

A total of 717 articles were identified, showing an upward trend in annual publications. Leading contributors included the United States, Italy, and China, with institutions such as the University of California System at the forefront. The Journal of Alzheimer's Disease emerged as the top publisher, while research published in Neurology garnered significant citations. Noteworthy authors encompassed Panza, Francesco; Frisardi, Vincenza; and Feldman, Eva L, with Kristine Yaffe being the most cited author (280 citations). Recent studies have focused on themes like "gut microbiota," "neuroinflammation," "fatty acids," and "microglia."

Conclusion

This bibliometric analysis summarizes the foundational knowledge structure in the realm of dementia and MetS from 2000 to 2023. By highlighting current research frontiers and trending topics, this analysis serves as a valuable reference for researchers in the field.

White matter microstructure alterations in type 2 diabetes mellitus and its correlation with cerebral small vessel disease and cognitive performance

Microstructural abnormalities of white matter fiber tracts are considered as one of the etiology of diabetes-induced neurological disorders. We explored the cerebral white matter microstructure alteration accurately, and to analyze its correlation between cerebral small vessel disease (CSVD) burden and cognitive performance in type 2 diabetes mellitus (T2DM). The clinical-laboratory data, cognitive scores [including mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), California verbal learning test (CVLT), and symbol digit modalities test (SDMT)], CSVD burden scores of the T2DM group (n = 34) and healthy control (HC) group (n = 21) were collected prospectively. Automatic fiber quantification (AFQ) was applied to generate bundle profiles along primary white matter fiber tracts. Diffusion tensor images (DTI) metrics and 100 nodes of white matter fiber tracts between groups were compared. Multiple regression analysis was used to analyze the relationship between DTI metrics and cognitive scores and CSVD burden scores. For fiber-wise and node-wise, DTI metrics in some commissural and association fibers were increased in T2DM. Some white matter fiber tracts DTI metrics were independent predictors of cognitive scores and CSVD burden scores. White matter fiber tracts damage in patients with T2DM may be characterized in specific location, especially commissural and association fibers. Aberrational specific white matter fiber tracts are associated with visuospatial function and CSVD burden.