Effects of n-3 PUFAs on Intestinal Mucosa Innate Immunity and Intestinal Microbiota in Mice after Hemorrhagic Shock Resuscitation

The Intestinal Microbiome after Traumatic Injury

The intestinal microbiome plays a critical role in host immune function and homeostasis. Patients suffering from-as well as models representing-multiple traumatic injuries, isolated organ system trauma, and various severities of traumatic injury have been studied as an area of interest in the dysregulation of immune function and systemic inflammation which occur after trauma. These studies also demonstrate changes in gut microbiome diversity and even microbial composition, with a transition to a pathobiome state. In addition, sex has been identified as a biological variable influencing alterations in the microbiome after trauma. Therapeutics such as fecal transplantation have been utilized to ameliorate not only these microbiome changes but may also play a role in recovery postinjury. This review summarizes the alterations in the gut microbiome that occur postinjury, either in isolated injury or multiple injuries, along with proposed mechanisms for these changes and future directions for the field.

Innate immunity and immunotherapy for hemorrhagic shock

Hemorrhagic shock (HS) is a shock result of hypovolemic injury, in which the innate immune response plays a central role in the pathophysiology ofthe severe complications and organ injury in surviving patients. During the development of HS, innate immunity acts as the first line of defense, mediating a rapid response to pathogens or danger signals through pattern recognition receptors. The early and exaggerated activation of innate immunity, which is widespread in patients with HS, results in systemic inflammation, cytokine storm, and excessive activation of complement factors and innate immune cells, comprised of type II innate lymphoid cells, CD4⁺ T cells, natural killer cells, eosinophils, basophils, macrophages, neutrophils, and dendritic cells. Recently, compelling evidence focusing on the innate immune regulation in preclinical and clinical studies promises new treatment avenues to reverse or minimize HS-induced tissue injury, organ dysfunction, and ultimately mortality. In this review, we first discuss the innate immune response involved in HS injury, and then systematically detail the cutting-edge therapeutic strategies in the past decade regarding the innate immune regulation in this field; these strategies include the use of mesenchymal stem cells, exosomes, genetic approaches, antibody therapy, small molecule inhibitors, natural medicine, mesenteric lymph drainage, vagus nerve stimulation, hormones, glycoproteins, and others. We also reviewed the available clinical studies on immune regulation for treating HS and assessed the potential of immune regulation concerning a translation from basic research to clinical practice. Combining therapeutic strategies with an improved understanding of how the innate immune system responds to HS could help to identify and develop targeted therapeutic modalities that mitigate severe organ dysfunction, improve patient outcomes, and reduce mortality due to HS injury.

Elevated Systemic and Intestinal Inflammatory Response Are Associated With Gut Microbiome Disorder After Cardiovascular Surgery

Systemic inflammatory response after cardiovascular surgery is associated with poor prognosis, to which gut barrier impairment is related. To investigate whether perioperative changes of the gut microbiome are associated with systemic and intestinal inflammatory response, we examined changes of the gut microbiome, intestinal homeostasis, and systemic inflammatory response in cardiovascular patients before (Pre) surgery and on the first defecation day [postoperative time 1 (Po1)] or a week [postoperative time 2 (Po2)] postsurgery. Markedly, the enhanced systemic inflammatory response was observed in Po1 and Po2 compared with that in Pre. In line with inflammatory response, impaired gut barrier and elevated gut local inflammation were observed in Po1 and Po2. Microbiome analysis showed a remarkable and steady decline of alpha diversity perioperatively. In addition, microbial composition in the postoperation period was characterized by significant expansion of Enterococcus along with a decrease in anaerobes (Blautia, Faecalibacterium, Bifidobacterium, Roseburia, Gemmiger, [Ruminococcus], and Coprococcus), which were typically health-associated bacteria. Spearman correlation analysis showed microbiome disorder was associated with enhanced systemic inflammatory response and intestinal dysbiosis. These results suggest that microbiome disorder was related to disturbed gut homeostatic and subsequently elevates plasma endotoxin and systemic inflammatory response after cardiovascular surgery. This study not only highlights gut microbiome would be considered in future clinical practice but also proposes a promising perspective of potential diagnostic and therapeutic options for perioperative management of cardiovascular surgery patients.

Microbiota dysbiosis and barrier dysfunction in inflammatory bowel disease and colorectal cancers: exploring a common ground hypothesis

Inflammatory bowel disease (IBD) is a multifactorial disease which arises as a result of the interaction of genetic, environmental, barrier and microbial factors leading to chronic inflammation in the intestine. Patients with IBD had a higher risk of developing colorectal carcinoma (CRC), of which the subset was classified as colitis-associated cancers. Genetic polymorphism of innate immune receptors had long been considered a major risk factor for IBD, and the mutations were also recently observed in CRC. Altered microbial composition (termed microbiota dybiosis) and dysfunctional gut barrier manifested by epithelial hyperpermeability and high amount of mucosa-associated bacteria were observed in IBD and CRC patients. The findings suggested that aberrant immune responses to penetrating commensal microbes may play key roles in fueling disease progression. Accumulative evidence demonstrated that mucosa-associated bacteria harbored colitogenic and protumoral properties in experimental models, supporting an active role of bacteria as pathobionts (commensal-derived opportunistic pathogens). Nevertheless, the host factors involved in bacterial dysbiosis and conversion mechanisms from lumen-dwelling commensals to mucosal pathobionts remain unclear. Based on the observation of gut leakiness in patients and the evidence of epithelial hyperpermeability prior to the onset of mucosal histopathology in colitic animals, it was postulated that the epithelial barrier dysfunction associated with mucosal enrichment of specific bacterial strains may predispose the shift to disease-associated microbiota. The speculation of leaky gut as an initiating factor for microbiota dysbiosis that eventually led to pathological consequences was proposed as the "common ground hypothesis", which will be highlighted in this review. Overall, the understanding of the core interplay between gut microbiota and epithelial barriers at early subclinical phases will shed light to novel therapeutic strategies to manage chronic inflammatory disorders and colitis-associated cancers.

Dietary Chlorella vulgaris Ameliorates Altered Immunomodulatory Functions in Cyclophosphamide-Induced Immunosuppressive Mice

Based on the well-known toxicity of cyclophosphamide (CYP) on the immune system, this research investigated the modulating effects of the long-term dietary Chlorella vulgaris (CV) supplementation on the immunosuppression induced by CYP in mice, in order to provide a novel dietary design to mitigate the side effects of CYP therapy. Control, CYP-treated, CYP + CV (6%), CYP + CV (12%) and CYP + CV (24%) were used for 6 weeks, CV supplement in diet recovered the significantly reduced immunological function in CYP treated mice. As CV may have a modulating function through the inducible expression of cytokines, we assayed the expressions of interleukin-2 (IL-2), interleukin-12 (IL-12), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). Our results suggested that CYP significantly reduced the lymphocytes proliferation and phagocytic activities of macrophages, and stimulated the production of IL-2, IL-12, TNF-α and IFN-γ and that this impairment has been successfully adjusted by CV supplementation. Treatment with the algae also enhanced the natural killer (NK) cells cytotoxicity, and ameliorate histological changes of the spleen in CYP-treated mice. Therefore, as we found in this study, a diet supplemented with whole CV has beneficial effects on CVP-induced immunosuppression, through its immunomodulatory potential.

Transcriptome analysis of Meloidogyne incognita encumbered by Pasteuria penetrans endospores provides new insights into bacteria and nematode interaction

Root-knot nematodes (RKN,Meloidogynespp.) are one of the most harmful pests in agriculture.Pasteuria penetrans, an obligate hyperparasite of RKN, is an effective biological control agent. However, little is known about the molecular mechanisms of interaction betweenP. penetransand the second-stage juvenile (J2) ofMeloidogyne incognita. Here, we used transcriptome sequencing to characterise the differential expression profiles between control J2 ofM. incognitaand J2 encumbered byP. penetransendospores. A total of 445 genes were found to be differentially expressed, including 406 up-regulated and 39 down-regulated genes. Thirty-seven putative immune-related genes encoding collagens, cytochrome P450, lysozymes and other active proteins were identified. Genes involved in the ‘biosynthesis of unsaturated fatty acids’ pathway and several core sets of immune effectors were up-regulated, indicating conserved immune mechanisms among different nematodes. Down-regulation of cytochrome P450-related genes might suggest a specific defence response ofM. incognitaencumbered byP. penetransendospores.