Hengxing Zhou

Spinal cord injury (SCI), for which there currently is no cure, is a heavy burden on patient physiology and psychology. The microenvironment of the injured spinal cord is complicated. According to our previous work and the advancements in SCI research, 'microenvironment imbalance' is the main cause of the poor regeneration and recovery of SCI. Microenvironment imbalance is defined as an increase in inhibitory factors and decrease in promoting factors for tissues, cells and molecules at different times and spaces. There are imbalance of hemorrhage and ischemia, glial scar formation, demyelination and re-myelination at the tissue's level. The cellular level imbalance involves an imbalance in the differentiation of endogenous stem cells and the transformation phenotypes of microglia and macrophages. The molecular level includes an imbalance of neurotrophic factors and their pro-peptides, cytokines, and chemokines. The imbalanced microenvironment of the spinal cord impairs regeneration and functional recovery. This review will aid in the understanding of the pathological processes involved in and the development of comprehensive treatments for SCI.

Study design: A literature review of worldwide epidemiology of spinal cord injury (SCI). Objectives: To review the epidemiological indicators of SCI, such as incidence, prevalence, demographic characteristics, etiology, level and severity of injury, complications and mortality. Setting: The Department of Orthopaedics, Tianjin Medical University General Hospital, ­Heping District, Tianjin, People’s Republic of China. Methods: We searched articles published in PubMed, Medline, EMBASE and the Web of ­Science between January 1993 and June 2017 using the key words “spinal cord injury”, “­traumatic spinal cord injury”, “non-traumatic spinal cord injury” and “epidemiology”. The incidence, etiology, prevalence, patient demographics, level and severity of injury, complications and mortality were reviewed from the articles. Results: The epidemiology of SCI has changed. Motor vehicle accidents and falls have become the most common reasons of injury gradually. Incidence of SCI varies by regions or countries, and it has gradually increased with the expansion of human activities. The number of male patients were significantly more than female, the average age of patients with SCI had a tendency to increase gradually. The cervical level of spine was the most common part of injury; there were more number of patients with tetraplegia than patients with paraplegia. Electrolyte disturbances, pulmonary infections, urinary tract infections and bedsores were the four most common complications. Conclusion: We must have a greater understanding of epidemiology to implement more preventative measures. The epidemiology in different regions is of significant difference, which may be resulted from economic, science and technology, medical, geographical and even social conditions. Therefore, we must establish appropriate intervention measures according to the particularity of population. Keywords: spinal cord injury, etiology, incidence, patient demographics, complications A Letter to the Editor has been received and published for this article.

OBJECTIVES: To evaluate the most up-to-date burden of traumatic brain injury (TBI) and spinal cord injury (SCI) and analyse their leading causes in different countries/territories. DESIGN: An analysis of Global Burden of Disease (GBD) data. SETTING: The epidemiological data were gathered from GBD Results Tool (1 January, 1990─31 December 2019) covering 21 GBD regions and 204 countries/ territories. PARTICIPANTS: Patients with TBI/SCI. MAIN OUTCOMES AND MEASURES: Absolute numbers and age-standardised rates/estimates of incidence, prevalence and years lived with disability (YLDs) of TBI/SCI by location in 2019, with their percentage changes from 1990 to 2019. The leading causes (eg, falls) of TBI/SCI in 204 countries/territories. RESULTS: Globally, in 2019, TBI had 27.16 million new cases, 48.99 million prevalent cases and 7.08 million YLDs. SCI had 0.91 million new cases, 20.64 million prevalent cases and 6.20 million YLDs. Global age-standardised incidence rates of TBI decreased significantly by -5.5% (95% uncertainty interval -8.9% to -3.0%) from 1990 to 2019, whereas SCI had no significant change (-6.1% (-17.3% to 1.5%)). Regionally, in 2019, Eastern Europe and High-income North America had the highest burden of TBI and SCI, respectively. Nationally, in 2019, Slovenia and Afghanistan had the highest age-standardised incidence rates of TBI and SCI, respectively. For TBI, falls were the leading cause in 74% (150/204) of countries/territories, followed by pedestrian road injuries (14%, 29/204), motor vehicle road injuries (5%, 11/204), and conflict and terrorism (2%, 4/204). For SCI, falls were the leading cause in 97% (198/204) of countries/territories, followed by conflict and terrorism (3%, 6/204). CONCLUSIONS: Global age-standardised incidence rates of TBI have decreased significantly since 1990, whereas SCI had no significant change. The leading causes of TBI/SCI globally were falls, but variations did exist between countries/territories. Policy-makers should continue to prioritise interventions to reduce falls, but priorities may vary between countries/territories.

STUDY DESIGN: Hospital-based retrospective review. OBJECTIVE: To describe the epidemiological characteristics and trends of traumatic spinal cord injury in Tianjin, China. SETTING: Tianjin Medical University General Hospital. METHODS: Medical records of 239 patients with traumatic spinal cord injury admitted to a general hospital from 1998 to 2009 were reviewed. Variables included gender, age, marital status, occupation, etiology, time of injury, level, and severity of injury. Epidemiological characteristics of different countries were compared. RESULTS: Over this period, the mean age of patients with traumatic spinal cord injury was 45.4 ± 14.1 years, and the male/female ratio was 4.6:1. In all, 86.2% were married. The leading cause was fall (52.3%), followed by motor vehicle collision (36.4%). The most common injury site was the cervical spinal cord, accounting for 82.0%. Incomplete tetraplegia made up for 59.4%, followed by complete tetraplegia (22.6%). Eight patients died after operation, six of whom died from respiratory complications. CONCLUSION: The results of this study are in accordance with that of most other developing countries; falls and motor vehicle collisions were the two leading causes, but the mean age was older. Percentage of the aged with traumatic spinal cord injury was increasing. The low-falls group tended to expand over this period. All these data indicated that the preventive programs should focus on the traffic accidents and falls, and more attention should be paid to the aged for the vulnerability to low fall.

BACKGROUND AND PURPOSE: Spinal cord injury (SCI) involves serious damage that can result in abnormal or absent motor and sensory functions and a disruption of autonomic function, and a series of pathological reactions occur after the injury. As a type of small non-coding RNA, microRNAs (miRNAs) have been verified to inhibit gene expression via post-transcriptional regulation. This review mainly focuses on recent advances regarding the roles of miRNAs following SCI. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adopted. The studies regarding the roles of miRNAs following SCI were identified through PubMed, Embase and Web of Science. We summarise the changes in expression levels of miRNAs and discuss the roles of miRNAs after SCI. RESULTS: A total of 77 empirical studies meeting the inclusion criteria were identified. Existing studies showed that miRNAs were temporally altered and had effects on apoptosis, inflammation, angiogenesis, astrogliosis, oligodendrocyte development, axonal regeneration and remyelination after SCI. The alteration of miRNAs and the regulative action of pathological reactions can also provide opportunities for potential therapeutic interventions. "miRNA replacement therapy" aims to transfer miRNAs into diseased cells via delivery techniques and improve targeting effectiveness in cells, and this novel therapeutic tool provides a promising technique to promote the repair of SCI and reduces functional deficits. CONCLUSIONS: This review is helpful for understanding the underlying mechanisms of SCI and the potential clinical value of miRNAs. miRNAs have the potential to be attractive tools and targets for novel diagnostic and therapeutic approaches of SCI.