The intestine is the largest immune and metabolic site in the body and is thus important for animal health.The integrity of the mucosal barrier and function are fundamental factors protecting the health of the intestine.Stress has been reported to have profound effects on the gastrointestinal tract,including altering gut permeability,the intestinal barrier,and homeostasis.Tryptophan is a functional essential amino acid that alters the gut microbiota and regulates intestine structural and functional change,thus contributing to host physiology and metabolism.Changes in tryptophan metabolism and its metabolites in brain and intestinal tissues during stress suggest that tryptophan may play an important role in the stress response.We therefore review the literature on the mechanisms underlying stress-related diseases and the role of tryptophan metabolism in the regulation of gut homeostasis,with particular focus on functional bowel disorders and their relationship to stress,to provide a theoretical foundation for targeting tryptophan in stress-related intestine diseases.

Cardiovascular disease is a health hazard to humans and systolic heart failure due to myocardial infarction is a major cause of death.It was previously thought that myocardial cells of the adult mammalian heart possess a limited ability to proliferate and self-renew.However,it has been widely reported that mammals have the ability to regenerate the myocardium,which is restricted to early postnatal life,and that it is strong enough to repair damaged heart tissue.The discovery of myocardial regeneration in neonatal hearts has provided an ideal animal model to investigate the mechanisms that affect myocardial regeneration,and many mechanisms that reverse myocardial cell cycle arrest and promote myocardial regeneration have been revealed.In this article,we review the factors affecting gene expression for myocardial regeneration(e.g.,ncRNAs and transcription factors),myocardial regeneration-related signaling pathways,and the regulation of myocardial regeneration by non-myocardial cells(e.g.,extracellular matrix,immune response,and epicardium)to provide directions for achieving myocardial regeneration after myocardial injury in adult mammals.

Neural loops are formed by interconnections between neurons through synaptic structures,which are the basic units of information transmission and processing in the brain and play an important role in the regulation of neural functions.After stroke,neural connections between the infarct and peri-infarct regions and the remote area are damaged,resulting in patients being at risk of neurological dysfunction or even disability.However,with advances in detection technology,an increasing number of studies are demonstrating that patients with stroke can undergo some functional recovery during the chronic phase,possibly via a mechanism related to the re-establishment of synaptic connections and neural circuits.Therefore,the development of specific technology to identify and manipulate neuronal activity patterns,as well as the use of high-resolution temporal and spatial imaging strategies to decipher these neurological processes,will allow us to understand the whole-brain network dynamics of stroke recovery and the mechanisms by which neural loop reestablishment occurs.Furthermore,we may be able to neurobiologically comprehend the closed-loop mechanisms that underlie the development of stroke pathology and their relationship to behavioral outcomes.Current technologies used for studying neural circuits include optogenetics,chemical genetics,in vivo calcium imaging,and functional magnetic resonance imaging.This article introduces the working principles of these four major technologies and focuses on summarizing the result of their respective application in resolving neural remodeling after stroke.We briefly analyze the application scenarios,advantages and disadvantages,and future development trends of each technique.This paper will help clinical and basic researchers to use these technologies to discover new therapeutic strategies and evaluate the effectiveness of rehabilitation strategies.