Corneal neuromediator profiles following laser refractive surgery

Laser refractive surgery is one of the most commonly performed procedures worldwide.In laser refractive surgery,Femtosecond Laser in Situ Keratomileusis and Refractive Lenticule Extraction have emerged as promising alternatives to microkeratome Laser in Situ Keratomileusis and Photorefractive Keratectomy.Following laser refractive surgery,the corneal nerves,epithelial and stromal cells release neuromediators,including neurotrophins,neuropeptides and neurotransmitters.Notably,nerve growth factor,substance P,calcitonin gene-related peptide and various cytokines are important mediators of neurogenic inflammation and corneal nerve regeneration.Alterations in neuromediator profiles and ocular surface parameters following laser refractive surgery are attributed to the surgical techniques and the severity of tissue insult induced.In this review,we will discuss the(1)Functions of neuromediators and their physiological and clinical significance;(2)Changes in the neuromediators following various laser refractive surgeries;(3)Correlation between neuromediators,ocular surface health and corneal nerve status;and(4)Future directions,including the use of neuromediators as potential biomarkers for ocular surface health following laser refractive surgery,and as adjuncts to aid in corneal regeneration after laser refractive surgery.

Neuroimmunomodulation by gut bacteria:Focus on inflammatory bowel diseases

Microbes colonize the gastrointestinal tract are considered as highest complex ecosystem because of having diverse bacterial species and 150 times more genes as compared to the human genome.Imbalance or dysbiosis in gut bacteria can cause dysregulation in gut homeostasis that subsequently activates the immune system,which leads to the development of inflammatory bowel disease(IBD).Neuromediators,including both neurotransmitters and neuropeptides,may contribute to the development of aberrant immune response.They are emerging as a regulator of inflammatory processes and play a key role in various autoimmune and inflammatory diseases.Neuromediators may influence immune cell’s function via the receptors present on these cells.The cytokines secreted by the immune cells,in turn,regulate the neuronal functions by binding with their receptors present on sensory neurons.This bidirectional communication of the enteric nervous system and the enteric immune system is involved in regulating the magnitude of inflammatory pathways.Alterations in gut bacteria influence the level of neuromediators in the colon,which may affect the gastrointestinal inflammation in a disease condition.Changed neuromediators concentration via dysbiosis in gut microbiota is one of the novel approaches to understand the pathogenesis of IBD.In this article,we reviewed the existing knowledge on the role of neuromediators governing the pathogenesis of IBD,focusing on the reciprocal relationship among the gut microbiota,neuromediators,and host immunity.Understanding the neuromediators and host-microbiota interactions would give a better insight in to the disease pathophysiology and help in developing the new therapeutic approaches for the disease.