Immuno-hematologic parameters following rodent spinal cord contusion are negatively influenced by high-fat diet consumption

Aging with spinal cord injury: A narrative review of consequences and challenges

Given the increase in life expectancy, aging with a pre-existing spinal cord injury (SCI) is becoming more common. This condition is challenging as compromised health status and functional independence can worsen. We aimed to provide an updated overview of the consequences of aging with SCI, highlighting the main challenges facing this population in a narrative review of the current literature we retrieved from the PubMed database from 2000 to 2022 on any aspect related to aging in persons with SCI. Here we address adverse circumstances that increase disability and hinder an active lifestyle, such as progressive physical deterioration, secondary health conditions, limitations in personal activity, changes in family and social support structures, aging of caregivers, and depletion of economic resources. Favorable changes are also observed, including psychosocial adjustments that improve quality of life. Additionally, various interventions are discussed to promote well-being, health, and social participation. Due to the relevance of this issue, people with SCI and all those who take care of them must have up-to-date information to carry out the necessary measures to promote healthy aging in a more inclusive social environment.

Altered chronic glycemic control in a clinically relevant model of rat thoracic spinal contusion

The lifetime risk for Type 2 diabetes mellitus remains higher in people with spinal cord injuries (SCIs) than in the able-bodied population. However, the mechanisms driving this disparity remain poorly understood. The goal of the present study was to evaluate the impact of a palatable high-fat diet (HFD) on glycemic regulation using a rodent model of moderate thoracic contusion. Animals were placed on either Chow or HFD and tolerance to glucose, insulin, and ENSURE mixed meal were investigated. Important targets in the gut-brain axis were investigated. HFD consumption equally induced weight gain in SCI and naïve rats over chow (CH) rats. Elevated blood glucose was observed during intraperitoneal glucose tolerance test in HFD-fed rats over CH-fed rats. Insulin tolerance test (ITT) was unremarkable among the three groups. Gavage of ENSURE resulted in high glucagon-like peptide 1 (GLP-1) release from SCI rats over naïve controls. An elevation in terminal total GLP-1 was measured, with a marked reduction in circulating dipeptidyl peptidase 4, the GLP-1 cleaving enzyme, in SCI rats, compared with naïve. Increased glucagon mRNA in the pancreas and reduced immunoreactive glucagon-positive staining in the pancreas in SCI rats compared with controls suggested increased glucagon turnover. Finally, GLP-1 receptor gene expression in the ileum, the primary source of GLP-1 production and release, in SCI rats suggests the responsivity of the gut to altered circulating GLP-1 in the body. In conclusion, the actions of GLP-1 and its preprohormone, glucagon, are markedly uncoupled from their actions on glucose control in the SCI rat. More work is required to understand GLP-1 in the human.

Nutrient composition influences the gut microbiota in chronic thoracic spinal cord-injured rats

Chronic spinal cord injury (SCI) results in an increased predisposition to various metabolic problems that can be exacerbated by consuming a diet rich in calories and saturated fat. In addition, gastrointestinal symptoms have been reported after SCI, including intestinal dysbiosis of the gut microbiome. The effects of both diet and SCI on the gut microbiome of adult male Long Evans rats euthanized 16 wk after injury were investigated. The rats were either thoracic spinal contused or received sham procedures. After 12 wk of either a low-fat or high-fat diet, cecal contents were analyzed, revealing significant microbial changes to every taxonomic level below the kingdom level. Shannon α diversity analyses demonstrated a significant difference in diversity between the groups based on the surgical condition of the rats. SCI produced a unique signature of changes in commensal bacteria that were significantly different than Sham. Specific changes in commensal bacteria as a result of diet manipulation had high fidelity with reports in the literature, such as Clostridia, Thiohalorhabdales, and Pseudomonadales. In addition, novel changes in commensal bacteria were identified that are unique dietary influences on SCI. Linear regression analysis on body fat and lean mass showed that a consequence of chronic SCI produces uncoupled associations between some commensal bacteria and body composition. In conclusion, despite tightly controlling the protein content and varying the carbohydrate and fat contents, Sham and SCI rats respond uniquely to diet. These data provide potential direction for therapeutic modulation of the microbiome to improve health and wellness following SCI.

Immune and Metabolic Biomarkers in a Rodent Model of Spinal Cord Contusion

STUDY DESIGN

Basic science animal research study.

OBJECTIVES

Using T10 spinal contused rats, we sought to identify molecular and circulating, metabolic and immune biomarkers during the subchronic and chronic recovery periods that may inform us concerning neurorehabilitation.

METHODS

Gene expression of the cord and ELISA were performed in 28 and 100 days in T10 injured rats and compared to sham-injured rats. Hundred-day injured rats were placed on either a low-fat or high-fat diet following the recovery phase. Linear regression analysis was performed between markers and locomotor score, body weight, body composition, and blood cholesterol and triglycerides.

RESULTS

Gene expression in the thoracic cord for complement marker, C1QC, dendritic cell marker, ITGAX, and cholesterol biosynthesis genes, FDFT1, HMCGR, LDLR, and SREBP1, were significantly associated with BBB score, body weight, composition, and other metabolic parameters. Circulating levels of these proteins, however, did not vary by injury or predict the level of locomotor recovery.

CONCLUSIONS

Identification of reliable circulating biomarkers that are durable and based on level of spinal injury are complicated by immune and metabolic comorbidities. Continued work is necessary to identify stable markers of disease progression.