Non-surgical management of spinal cord injury

Macromolecule-based hydrogels nanoarchitectonics with mesenchymal stem cells for regenerative medicine: A review

The role of regenerative medicine in clinical therapies is becoming increasingly vital. Under specific conditions, mesenchymal stem cells (MSCs) are capable of differentiating into mesoblastema (i.e., adipocytes, chondrocytes, and osteocytes) and other embryonic lineages. Their application in regenerative medicine has attracted a great deal of interest among researchers. To maximize the potential applications of MSCs, materials science could provide natural extracellular matrices and provide an effective means to understand the various mechanisms of differentiation for the growth of MSCs. Pharmaceutical fields are represented among the research on biomaterials by macromolecule-based hydrogel nanoarchitectonics. Various biomaterials have been used to prepare hydrogels with their unique chemical and physical properties to provide a controlled microenvironment for the culture of MSCs, laying the groundwork for future practical applications in regenerative medicine. This article currently describes and summarizes the sources, characteristics, and clinical trials of MSCs. In addition, it describes the differentiation of MSCs in various macromolecule-based hydrogel nanoarchitectonics and highlights the preclinical studies of MSCs-loaded hydrogel materials in regenerative medicine conducted over the past few years. Finally, the challenges and prospects of MSC-loaded hydrogels are discussed, and the future development of macromolecule-based hydrogel nanoarchitectonics is outlined by comparing the current literature.

Stem cells in the treatment of chronic spinal cord injury: evaluation of somatosensitive evoked potentials in 39 patients

STUDY DESIGN

A prospective, non-randomized clinical series trial.

OBJECTIVE

To evaluate the effect of autogenous undifferentiated stem cell infusion for the treatment of patients with chronic spinal cord injury (SCI) on somatosensory evoked potentials (SSEPs).

SETTING

A public tertiary hospital in São Paulo, Brazil.

METHODS

Thirty-nine consecutive patients with diagnosed complete cervical and thoracic SCI for at least 2 years and with no cortical response in the SSEP study of the lower limbs were included in the trial. The trial patients underwent peripheral blood stem cell mobilization and collection. The stem cell concentrate was cryopreserved and reinfused through arteriography into the donor patient. The patients were followed up for 2.5 years and submitted to SSEP studies to evaluate the improvement in SSEPs after undifferentiated cell infusion.

RESULTS

Twenty-six (66.7%) patients showed recovery of somatosensory evoked response to peripheral stimuli after 2.5 years of follow-up.

CONCLUSION

The 2.5-year trial protocol proved to be safe and improved SSEPs in patients with complete SCI.

SPONSORSHIP

None.

Investigation of the dose-dependent neuroprotective effects of agmatine in experimental spinal cord injury: a prospective randomized and placebo-control trial

OBJECT

No definitive treatment for spinal cord injuries (SCIs) exists, and more research is required. The use of agmatine [4-(aminobutyl)-guanidine-NH2-CH2-CH2-CH2-CH2-NH-C(-NH2)(=NH)], a guanidinium compound formed by decarboxylation of L-arginine by arginine decarboxylase, is a neurotransmitter-neuromodulator with both N-methyl-D-aspartate receptor (NMDAR)-antagonizing and nitric oxide synthase (NOS)-inhibiting activities. The purpose of this study was to demonstrate the dose-dependent activity of agmatine, an inducible NOS (iNOS) inhibitor and selective NMDAR antagonist, on biochemical and functional recovery in an experimental rat SCI model.

METHODS

This study involved 40 Wistar albino male rats. The rats were subjected to sleep-awake cycles for 7 days before surgery. In each group, general anesthesia was induced by a 60-mg/kg ketamine injection. For the surgical SCI model, a Yaşargil aneurysm clip was placed in the spinal cord. The study was conducted in the following four main groups: Group I (control group) laminectomy only; Group II, trauma-only group and SCI; Group III, laminectomy, SCI and agmatine 50 mg/kg for 10 days; and Group IV, laminectomy, SCI, and agmatine 100 mg/kg for 10 days. On Day 1, no statistical difference was observed in any group (p < 0.005, analysis of variance [ANOVA] and the Fisher protected least significant difference [PLSD]). On Day 2, no statistical difference was noted among Groups II, III, and IV (p = 0.27, p = 0.42, and p = 0.76, respectively; ANOVA and Fisher PLSD). Beginning on Day 3, recovery in Groups III and IV differed significantly from that in Group II (p < 0.005, ANOVA and Fisher PLSD), and a statistically significant difference between Groups III and IV was observed, which also was present on Days 5, 7, and 10 (p = 0.003, p = 0.0024, and p = 0.0036, respectively; ANOVA and Fisher PLSD). Several observations were noteworthy: motor function scores were reduced significantly in the spinal cord-injured rats compared with the controls (p < 0.005); on Day 1, the agreement of motor function scores in rats in each SCI group indicated that the traumatic event had been replicated equally across all groups (p = 0.59, p = 0.59, and p = 0.28); a statistically significant difference in motor function scores developed on Day 3 between the rats subjected to trauma alone (Group II) and those treated with agmatine (Groups III and IV) (p < 0.005); and no statistically significant intergroup difference in motor function existed at any postinjury interval between the 50- and 100-mg/kg/day agmatine-treated rats (p > 0.005).

CONCLUSIONS

Agmatine administration following SCI was shown to reduce NO levels significantly. No statistically significant intergroup difference in the reduction of NO levels was found between rats treated with 50- and 100-mg/kg/day doses of agmatine. Administration of a 100-mg/kg/day dose of agmatine reduced the NO levels to those measured in controls. The authors conclude that with additional studies into the role of agmatine, this drug may be helpful in the treatment of patients with SCIs.

Iatrogenic paraplegia in spinal surgery

INTRODUCTION

Paraplegia as a result of a surgical spinal procedure is a rare complication. The risk cannot be precisely quantified due to the lack of current data. The aim of this study was to record a sufficiently large number of major spinal operations, especially extended methods in scoliosis surgery. Hereby, a reliable statement regarding the risk of severe neurological complications with these surgical techniques should be possible. First, a retrospective analysis of patients from a German spine centre (spinal fusion) and a survey of 17 German centres of spinal surgery were conducted for the retrospective acquisition of severe iatrogenic neurological complications.

MATERIALS AND METHODS

The study included 1194 patients who underwent a spinal fusion during the period 1992-2002. The incidents of postoperative paraplegia are described in detail, and case studies done. Possible causes, methods of intraoperative monitoring and options of therapy are discussed according to research in relevant publications. Additionally, severe neurological complications of 3115 spinal operations were recorded in a standardised survey conducted throughout major German spinal centres.

RESULTS

Of the 1194 patients surveyed, 7 (0.59%) experienced a postsurgical complete or incomplete paraplegia. In 3 of the recorded cases, the cause could be identified. The survey of 3115 scoliosis surgeries showed that iatrogenic paraplegia occurred with a frequency of 0.55%. The risks associated with short spinal fusions (0.14%), cervical discectomies (0.07%) and lumbar discectomies (0.03%) are considerably less.

CONCLUSION

Operative treatment of scoliosis with a high degree of correction carries a risk of neurological complications of about 0.5%. Mechanical as well as ischaemic damage to the spinal cord can be detected early by means of consistent intraoperative neuromonitoring.