Poly(glycerol sebacate) combined with chondroitinase ABC promotes spinal cord repair in rats

A systematic review and meta-analysis of chondroitinase ABC promotes functional recovery in rat models of spinal cord injury

BACKGROUND

To comprehensively assess the neurologic recovery potential of chondroitinase ABC (ChABC) in rats after spinal cord injury (SCI).

METHODS

The PubMed, Embase, ScienceDirect, Web of Science, and China National Knowledge Infrastructure databases were searched for animal experiments that evaluated the use of ChABC in the treatment of SCI up to November 2022. Studies reporting neurological function using the Basso, Beattie, and Bresnahan (BBB) scale, as well as assessments of cavity area, lesion area, and glial fibrillary acidic protein (GFAP) levels, were included in the analysis.

RESULTS

A total of 46 studies were ultimately selected for inclusion. The results of the study showed that rats with SCI that received ChABC therapy exhibited a significant improvement in locomotor function after 7 days compared with controls (32 studies, weighted mean difference (WMD) = 0.58, [0.33, 0.83], p < 0.00001). Furthermore, the benefits of ChABC therapy were maintained for up to 28 days according to BBB scale. The lesion area was reduced by ChABC (5 studies, WMD = -20.94, [-28.42, -13.46], p < 0.00001). Meanwhile, GFAP levels were reduced in the ChABC treatment group (8 studies, WMD = -29.15, [-41.57, -16.72], p < 0.00001). Cavity area is not statistically significant. The subgroup analysis recommended that a single injection of 10 μL (8 studies, WMD = 2.82, [1.99, 3.65], p < 0.00001) or 20 U/mL (4 studies, WMD = 2.21, [0.73, 3.70], p = 0.003) had a better effect on improving the function. The funnel plot of the BBB scale was found to be essentially symmetrical, indicating a low risk of publication bias.

CONCLUSIONS

This systematic review and meta-analysis has indicated that ChABC could improve functional recovery in rats after SCI.

Different methods of synthesizing poly(glycerol sebacate) (PGS): A review

Poly(glycerol sebacate) (PGS) is a biodegradable elastomer that has attracted increasing attention as a potential material for applications in biological tissue engineering. The conventional method of synthesis, first described in 2002, is based on the polycondensation of glycerol and sebacic acid, but it is a time-consuming and energy-intensive process. In recent years, new approaches for producing PGS, PGS blends, and PGS copolymers have been reported to not only reduce the time and energy required to obtain the final material but also to adjust the properties and processability of the PGS-based materials based on the desired applications. This review compiles more than 20 years of PGS synthesis reports, reported inconsistencies, and proposed alternatives to more rapidly produce PGS polymer structures or PGS derivatives with tailor-made properties. Synthesis conditions such as temperature, reaction time, reagent ratio, atmosphere, catalysts, microwave-assisted synthesis, and PGS modifications (urethane and acrylate groups, blends, and copolymers) were revisited to present and discuss the diverse alternatives to produce and adapt PGS.

Sustained delivery of chABC improves functional recovery after a spine injury

INTRODUCTION

Chondroitinase ABC (chABC) is an enzyme could improve regeneration and thereby improving functional recovery of spinal cord injury (SCI) in rodent models. Degradation of the active enzyme and diffusion away from the lesion are the causes of using hydrogels as a scaffold to deliver the chABC into the lesion site. In this meta-analysis, we investigated the effects of chABC embedded in a scaffold or hydrogel on the functional recovery after SCI.

METHOD

Databases were searched based on keywords related to chABC and spinal cord injury (SCI). Primary and secondary screening was performed to narrow down study objectives and inclusion criteria, and finally the data were included in the meta-analysis. The standard mean difference of the score of the functional recovery that measured by Basso, Beattie, Bresnahan (BBB) test after SCI was used to analyze the results of the reported studies. Subgroup analysis was performed based on SCI model, severity of SCI, transplantation type, and the follow-up time. Quality control of articles was also specified.

RESULTS

The results showed that embedding chABC within the scaffold increased significantly the efficiency of functional recovery after SCI in animal models (SMD = 1.95; 95% CI 0.71-3.2; p = 0.002) in 9 studies. SCI model, severity of SCI, injury location, transplantation type, and the follow-up time did not affect the overall results and in all cases scaffold effect could not be ignored. However, due to the small number of studies, this result is not conclusive and more studies are needed.

CONCLUSION

The results could pave the way for the use of chABC embedded in the scaffold for the treatment of SCI and show that this method of administration is superior to chABC injection alone.

Poly(Glycerol Sebacate) in Biomedical Applications-A Review of the Recent Literature

Poly(glycerol sebacate) (PGS) continues to attract attention for biomedical applications owing to its favorable combination of properties. Conventionally polymerized by a two-step polycondensation of glycerol and sebacic acid, variations of synthesis parameters, reactant concentrations or by specific chemical modifications, PGS materials can be obtained exhibiting a wide range of physicochemical, mechanical, and morphological properties for a variety of applications. PGS has been extensively used in tissue engineering (TE) of cardiovascular, nerve, cartilage, bone and corneal tissues. Applications of PGS based materials in drug delivery systems and wound healing are also well documented. Research and development in the field of PGS continue to progress, involving mainly the synthesis of modified structures using copolymers, hybrid, and composite materials. Moreover, the production of self-healing and electroactive materials has been introduced recently. After almost 20 years of research on PGS, previous publications have outlined its synthesis, modification, properties, and biomedical applications, however, a review paper covering the most recent developments in the field is lacking. The present review thus covers comprehensively literature of the last five years on PGS-based biomaterials and devices focusing on advanced modifications of PGS for applications in medicine and highlighting notable advances of PGS based systems in TE and drug delivery.

Polyglycerol Hyperbranched Polyesters: Synthesis, Properties and Pharmaceutical and Biomedical Applications

In a century when environmental pollution is a major issue, polymers issued from bio-based monomers have gained important interest, as they are expected to be environment-friendly, and biocompatible, with non-toxic degradation products. In parallel, hyperbranched polymers have emerged as an easily accessible alternative to dendrimers with numerous potential applications. Glycerol (Gly) is a natural, low-cost, trifunctional monomer, with a production expected to grow significantly, and thus an excellent candidate for the synthesis of hyperbranched polyesters for pharmaceutical and biomedical applications. In the present article, we review the synthesis, properties, and applications of glycerol polyesters of aliphatic dicarboxylic acids (from succinic to sebacic acids) as well as the copolymers of glycerol or hyperbranched polyglycerol with poly(lactic acid) and poly(ε-caprolactone). Emphasis was given to summarize the synthetic procedures (monomer molar ratio, used catalysts, temperatures, etc.,) and their effect on the molecular weight, solubility, and thermal and mechanical properties of the prepared hyperbranched polymers. Their applications in pharmaceutical technology as drug carries and in biomedical applications focusing on regenerative medicine are highlighted.