Fast Maturation of Splenic Dendritic Cells Upon TBI Is Associated With FLT3/FLT3L Signaling

Research progress on digestive disorders following traumatic brain injury

Traumatic brain injury (TBI) is a prevalent disease that poses a significant threat to global public health. Digestive dysfunction, as a common complication, is of particular importance to understand its pathogenesis, diagnostic criteria, and relevant treatment strategies. TBI can affect digestive function through inflammatory immune responses, the enteric nervous system, and hormonal levels. Furthermore, TBI can also impact neurologic recovery through bidirectional communication along the brain-gut axis. Therefore, this article aims to summarize the underlying mechanisms and further explore individualized feeding strategies, therapeutic approaches, long-term prognosis for TBI patients, as well as recent advancements in related technologies. Further understanding of the pathogenesis of digestive system dysfunction after TBI on the basis of the interaction of gut-brain axis is conducive to more future therapies to treat TBI and improve the long-term prognosis of patients through improving digestive function, and achieve good clinical efficacy.

Enhancing daily living and cognitive functions in traumatic brain injury patients through Orem's self-care theory

Introduction

This research seeks to investigate how early rehabilitation nursing, guided by Orem's self-care theory, affects cognitive function, neurological function, and daily living skills in individuals who have suffered a traumatic brain injury (TBI).

Methods

A study was conducted with 108 patients with traumatic brain injury who were hospitalized at our facility from January 2021 to March 2023. Based on their admission dates, the participants were separated into a control group (n = 56) and an observation group (n = 52). The control group received standard nursing care, while the observation group received a combination of conventional treatment and nursing interventions based on Orem's self-care model. The research assessed alterations in the ability to perform daily tasks (Activities of Daily Living, ADL), neurological health (National Institutes of Health Stroke Scale, NIHSS; Glasgow Coma Scale, GCS), and cognitive abilities (Montreal Cognitive Assessment Scale, MoCA; Mini-Mental State Examination, MMSE) in both sets of participants prior to and following 4 and 8 weeks of nursing assistance.

Results

Following the intervention, the group being observed showed notably increased ADL scores at 4 weeks (p < 0.001) and 8 weeks (p < 0.001) in comparison to the control group. At 4 weeks and 8 weeks after nursing, the observation group had significantly lower NIHSS scores compared to the control group (4 weeks after nursing, p = 0.03; 4 weeks after nursing, p < 0.001). GCS score comparison showed the similar results (4 weeks after nursing, p = 0.013; 4 weeks after nursing, p = 0.003). Moreover, the participants in the observation group had notably higher MoCA and MMSE scores in comparison with the control group 4 and 8 weeks after nursing (all p < 0.001).

Conclusion

Orem's self-care theory improves patients' cognitive, neurological, and daily living functions of TBI patients during early rehabilitation nursing. This method helps enhance the level of care given by healthcare professionals, leading to more thorough and compassionate nursing care for patients.

GPR55 Inactivation Diminishes Splenic Responses and Improves Neurological Outcomes in the Mouse Ischemia/Reperfusion Stroke Model

Although strokes are frequent and severe, treatment options are scarce. Plasminogen activators, the only FDA-approved agents for clot treatment (tissue plasminogen activators (tPAs)), are used in a limited patient group. Moreover, there are few approaches for handling the brain's inflammatory reactions to a stroke. The orphan G protein-coupled receptor 55 (GPR55)'s connection to inflammatory processes has been recently reported; however, its role in stroke remains to be discovered. Post-stroke neuroinflammation involves the central nervous system (CNS)'s resident microglia activation and the infiltration of leukocytes from circulation into the brain. Additionally, splenic responses have been shown to be detrimental to stroke recovery. While lymphocytes enter the brain in small numbers, they regularly emerge as a very influential leukocyte subset that causes secondary inflammatory cerebral damage. However, an understanding of how this limited lymphocyte presence profoundly impacts stroke outcomes remains largely unclear. In this study, a mouse model for transient middle cerebral artery occlusion (tMCAO) was used to mimic ischemia followed by a reperfusion (IS/R) stroke. GPR55 inactivation, with a potent GPR55-specific antagonist, ML-193, starting 6 h after tMCAO or the absence of the GPR55 in mice (GPR55 knock out (GPR55ko)) resulted in a reduced infarction volume, improved neurological outcomes, and decreased splenic responses. The inhibition of GPR55 with ML-193 diminished CD4+T-cell spleen egress and attenuated CD4+T-cell brain infiltration. Additionally, ML-193 treatment resulted in an augmented number of regulatory T cells (Tregs) in the brain post-tMCAO. Our report offers documentation and the functional evaluation of GPR55 in the brain-spleen axis and lays the foundation for refining therapeutics for patients after ischemic attacks.

Traumatic brain injury alters dendritic cell differentiation and distribution in lymphoid and non-lymphoid organs

Background

Pathophysiological consequences of traumatic brain injury (TBI) mediated secondary injury remain incompletely understood. In particular, the impact of TBI on the differentiation and maintenance of dendritic cells (DCs), which are regarded as the most professional antigen presenting cells of the immune system, remains completely unknown. Here, we report that DC-differentiation, maintenance and functions are altered on day 3 and day 7 after TBI.

Methods

Long bones, spleen, peripheral lymph nodes (pLNs), mesenteric lymph nodes (mLNs), liver, lungs, skin and blood were collected from mice with either moderate-level cortical impact (CCI) or sham on day 1, day 3 or day 7 after TBI. Bone marrow cells were isolated from the tibias and femurs of hind limb through flushing. Tissues were digested with Collagenase-D and DNase I. Skin biopsies were digested in the presence of liberase + DNase I. Single cell suspensions were made, red blood cells were lysed with Ammonium chloride (Stem Cell Technology) and subsequently filtered using a 70 μM nylon mesh. DC subsets of the tissues and DC progenitors of the BM were identified through 10-color flow cytometry-based immunophenotyping studies. Intracellular reactive oxygen species (ROS) were identified through H2DCFDA staining.

Results

Our studies identify that; (1) frequencies and absolute numbers of DCs in the spleen and BM are altered on day 3 and day 7 after TBI; (2) surface expression of key molecules involved in antigen presentation of DCs were affected on day 3 and day 7 after TBI; (3) distribution and functions of tissue-specific DC subsets of both circulatory and lymphatic systems were imbalanced following TBI; (4) early differentiation program of DCs, especially the commitment of hematopoietic stem cells to common DC progenitors (CDPs), were deregulated after TBI; and (5) intracellular ROS levels were reduced in DC progenitors and differentiated DCs on day 3 and day 7 after TBI.

Conclusions

Our data demonstrate, for the first time, that TBI affects the distribution pattern of DCs and induces an imbalance among DC subsets in both lymphoid and non-lymphoid organs. In addition, the current study demonstrates that TBI results in reduced levels of ROS in DCs on day 3 and day 7 after TBI, which may explain altered DC differentiation paradigm following TBI. A deeper understanding on the molecular mechanisms that contribute to DC defects following TBI would be essential and beneficial in treating infections in patients with acute central nervous system (CNS) injuries, such as TBI, stroke and spinal cord injury.