Stem cell transplantation for spinal cord injury: a meta-analysis of treatment effectiveness and safety.

Abstract

OBJECTIVE:The aim of this study was to evaluate the effectiveness and safety of stem cell transplantation for spinal cord injury (SCI).DATA SOURCES:PubMed, EMBASE, Cochrane, China National Knowledge Infrastructure, China Science and Technology Journal, Wanfang, and SinoMed databases were systematically searched by computer to select clinical randomized controlled trials using stem cell transplantation to treat SCI, published between each database initiation and July 2016.DATA SELECTION:Randomized controlled trials comparing stem cell transplantation with rehabilitation treatment for patients with SCI. Inclusion criteria: (1) Patients with SCI diagnosed according to the American Spinal Injury Association (ASIA) International standards for neurological classification of SCI; (2) patients with SCI who received only stem cell transplantation therapy or stem cell transplantation combined with rehabilitation therapy; (3) one or more of the following outcomes reported: outcomes concerning neurological function including sensory function and locomotor function, activities of daily living, urination functions, and severity of SCI or adverse effects. Studies comprising patients with complications, without full-text, and preclinical animal models were excluded. Quality of the included studies was evaluated using the Cochrane risk of bias assessment tool and RevMan V5.3 software, provided by the Cochrane Collaboration, was used to perform statistical analysis.OUTCOME MEASURES:ASIA motor score, ASIA light touch score, ASIA pinprick score, ASIA impairment scale grading improvement rate, activities of daily living score, residual urine volume, and adverse events.RESULTS:Ten studies comprising 377 patients were included in the analysis and the overall risk of bias was relatively low level. Four studies did not detail how random sequences were generated, two studies did not clearly state the blinding outcome assessment, two studies lacked blinding outcome assessment, one study lacked follow-up information, and four studies carried out selective reporting. Compared with rehabilitation therapy, stem cell transplantation significantly increased the lower limb light touch score (odds ratio (OR) = 3.43, 95% confidence interval (CI): 0.01 – 6.86, P = 0.05), lower limb pinprick score (OR = 3.93, 95%CI: 0.74 – 7.12, P = 0.02), ASI grading rate (relative risk (RR) = 2.95, 95%CI: 1.64 – 5.29, P = 0.0003), and notably reduced residual urine volume (OR = –8.10, 95%CI: –15.09 to –1.10, P = 0.02). However, stem cell transplantation did not significantly improve motor score (OR = 1.89, 95%CI: –0.25 to 4.03, P = 0.08) or activities of daily living score (OR = 1.12, 95%CI: –1.17 to 4.04, P = 0.45). Furthermore, stem cell transplantation caused a high rate of mild adverse effects (RR = 14.49, 95%CI: 5.34 – 34.08, P < 0.00001); however, these were alleviated in a short time.CONCLUSION:Stem cell transplantation was determined to be an efficient and safe treatment for SCI and simultaneously improved sensory and bladder functions. Although associated minor and temporary adverse effects were observed with transplanted stem cells, spinal cord repair and axon remyelination were apparent. More randomized controlled trials with larger sample sizes and longer follow-up times are needed to further validate the effectiveness of stem cell transplantation in the treatment of SCI.